The episodes of Nichijou were shown weekly on TV Aichi, excluding the original video animation (OVA), beginning on April 3, 2011 and ending on September 25, 2011. The OVA, titled "Nichijou Episode 0", was released on March 12, bundled with the sixth volume of the Nichijou manga, before the series premiered. Below is a list of the episodes of Nichijou and their summaries.
Mio Naganohara tries to comfort her friend Yuuko Aioi when she gets a 1% score on a test. Meanwhile, robotic girl Nano Shinonome tries to give the young Hakase, who has a cold, some medicine, which she refuses to eat, and tries to get advice from their talking cat, Sakamoto. Finally Hakase eats the medicine that Shinonome mixed the medicine with pudding called Crunchy pudding. Later, Yuuko, Mio and their friend Mai Minakami go on a train ride, which is completely empty at this time of the day.
While chasing after a cat that stole her breakfast, Nano runs into a student and blows up and winds herself up on a roof with a missing arm. Yuuko goes through desperate means to keep her octopus sausage from being sullied, while Koujirou Sasahara makes a scene at the school's opening ceremony over bringing his goat to school only to be shot and reprimanded by Misato Tachibana and Yuuko tricks Mio into pressing the fire alarm. Later, Nano begs her creator, Hakase, to remove the noticeable wind-up key on her back, but she refuses because she thinks it is cute.
After running late from school, Mio ends up being chased by a girl wearing a bear mask, which turns out to be her older sister Yoshino Naganohara playing a prank on her. Meanwhile, Nano is shocked to find Hakase has modified her body to produce desserts. Later, Mio lends Yuuko her notebook only to remember that she ended up drawing an erotic sketch of Koujirou in there, and attempts to get it back. Meanwhile, Misato tries to get Koujirou to cooperate with her on the festival committee seriously.
Yuuko gets the feeling that Mai is mad at her and tries to apologize in various ways, only to find out she was wearing headphones. Meanwhile, Nano and Hakase finds a black cat and names it Sakamoto. Hakase makes a special scarf which allows Sakamoto to speak, although he ends up speaking in a rather condescending tone towards the two. Yuuko has an arm wrestling match with Mai only to lose repeatedly to the latter.
Guidance counselor Izumi Sakurai has trouble enforcing the rules to school's students. Meanwhile, Nano and Hakase go grocery shopping where they are surprised to find a snowman on sale. Later, Sakamoto's desire to be the authority figure is wavered by his cat-like tendencies. Mai tells Yuuko that she has feelings for her which leaves Yuuko flabbergasted only to learn it is one of Mai's many pranks on her.
Tsuyoshi Nakanojou visits a medium in order to debunk the supernatural but fails. Yuuko and Mai play Rock-paper-scissors except Mai doesn't follow the rules of the game exactly. Hakase tries to fix Nano's Daruma doll only to make it worse. Yuuko decides to draw for Ms. Izumi's next quiz paper which catches Mio attention as she is stunned that Ms. Izumi likes Yuuko amateur drawing. Despite her drawings are better than Yuuko's, Ms. Izumi doesn't find Mio drawings cool which in her anger and absentmindedness, Mio accidentally draws a half naked picture of Koujirou which unfortunately for her, Ms. Izumi does put it in the quiz paper.
Mio and Yuuko play a game of picture shiritori, with Mio becoming increasingly shocked by Yuuko's bad spelling. While standing out in the hallway, Yuuko becomes speechless as she bears witness to a life or death battle between Principal Shinonome and a deer. Meanwhile, Nano catches a cockroach under a bowl, but becomes scared as to what to do next. As Yuuko, Mio and Mai go camping, Yuuko and Mio accidentally ruin their food, leading to some heated arguments between the two.
An evil man named Dolph kidnaps the King Albert and pursues his daughter Princess Starla, seeking two wooden cubes that will allow him to take over the kingdom. However, he randomly dies after tripping over, allowing the princess to regain control of his minions. One of the minions finds both the cubes, but accidentally knocks them out the blimp window, where it's revealed to be Yuuko's dream concerning how Mio got her hairbands. Back in reality, Manabu Takasaki becomes conflicted between his feelings for Sakurai and his duty as a teacher. Meanwhile, Yoshino encounters Nano and has fun teasing her. Later, Hakase, Nano and Sakamoto play baseball but have no idea how to play it.
Yuuko tells various jokes to make Mio and Mai laugh, but she is devastated by the fact that none of them succeed. Misato tries very hard to hide her feelings for Koujirou, however her embarrassment gives her away.
Mio is angry with her older sister Yoshino for ruining her cakes in order to play jokes on her. Yuuko, Mio and Mai eat at a Soba restaurant, but Yuuko gets impatient when Mio's and Mai's dishes arrive while her order of vegetable tendon has not. Yuuko is unable to sleep due to mosquitoes in her room. Nano punishes Hakase for eating snacks before dinner. Mio is tricked by Yoshino to take a part-time job as a Daifuku mascot at a Daifuku stand much to her embarrassment and annoyance.
Yuuko arrives late for class but is unable to enter due to the various traps set up by Mai. Haruna Annaka goes to the park to eat Nagashi sōmen but the food is being served by a mad woman. After Nano praises how mature her ponytail looks, Hakase decides to act like an adult much to Nano's worry and Sakamoto's annoyance. Yuuko doesn't want to do her homework and goes deep into thought about her future.
After finally recovering at home from a three-day cold, Yuuko panics when she learns of tomorrow's school test. She struggles against her lazy-like behavior while trying to study but ends up writing poems. Vice-principal Kousuke Oura has some nostalgic moments concerning his lonely and blurred past. Hakase makes a super glue to trap Sakamoto and Nano, but not only does she trap them, she also traps herself, almost killing Sakamoto in the process. Later, Hakase plays "Who is it?" with Nano. Sakamoto leaves the room, leaving the two alone, only to trap himself again on the super glue. Yuuko tries to relax and remain calm in order to focus and resolve the test, but she runs out of time before that happens.
Yuuko starts the day with a great mood, but she panics once at school after realizing she forgot her homework at home. Misato Tachibana becomes flustered when Sasahara tries to help her choose a juice from the vending machine. When she randomly ends up picking the one he recommended, she fires an FN P90 PDW at him. Annaka goes to a shooting stall where the only prizes are eggplants and boxes of candy. After several tries, she discovers the prizes are all nailed down and is told to never come back. Mio and Yuuko go to a theme park, and Yuuko goes into a zombie-like state when she learns that Mio lost her wallet with all her money. Hakase attaches a wind up key on her back similar to Nano's and tries to act like her, but she does not last long since she cannot get used to it. Nano tries to seize the chance by having Hakase remove her key while they are switching roles, but fails.
Through Sakamoto, Hakase learns of Nano's wish to go to school though she misunderstands that Nano wants to leave her. Despite having a serious fever, Yuuko still goes to school to perform some tricks she practiced for Mio albeit without success. Sakamoto is afraid that Hakase is being spoiled by Nano when she gives in to Hakase's persistence and buys her sweets. Yuuko scores 80 in a test. Mio finds her overreaction too annoying. On a stormy night, Hakase has Nano escort her to the bathroom. She asks Nano if she really wants to go to school. The next day, Hakase brings her a high school uniform to her surprise and joy.
Nano begins her first day at high school, but becomes paranoid about hiding the fact that she's a robot, though everyone else pretty much figures it out upon seeing her. A boy named Makoto Sakurai decides to join the Igo-Soccer Club, revealing to the club's president, Kenzaburou Daiku, about what one actually entails. Later, Mio gets into a heated argument with Yuuko after she mishears her request for lunch.
Mio and Yuuko attempt to prove that Nano is a robot only to fail, but Mai manages to film evidence. Nano tries to convince Hakase to remove the wind-up key on her back as it's hindering her school life, but gets mad and shoots Hakase with a pellet gun everytime a dubious item comes out of her body. Scientist Kana Nakamura plans to kidnap Nano, as she is interested about her robotic nature. When her drugged coffee fails to work on Nano, she decides to use a taser, only to mistakenly use it on Tsuyoshi. Mr. Takasaki becomes conflicted upon seeing Ms. Izumi and Makoto being close, unaware that they are siblings. Nano asks Hakase about the wind-up key again, but much to her chagrin, Hakase has installed a reaction feature that causes Nano to react in insane ways every time Hakase makes a joke.
Yuuko goes to a reopened coffee shop called Daiku Café to order coffee but due to its confusing menu names and the shop's employee Tamamura not helping explaining it to her, Yuuko gives up and orders a small cup of Espresso. Later, Yuuko meets up with Mio but when a police officer suspects Mio is the culprit for putting counterfeit dollars in vending machines in the area, he confiscates her bag which contains a Yaoi doujin starring Koujirou. Mio freaks out and keeps her doujin a secret by knocking out anyone who reads it including the officer, Yuuko, an old man and Koujirou's goat. While doing their school work at a fast food restaurant, Yuuko plays a game with Mio and Mai to guess which one of her hands she has hidden an eraser in, which Mai wins by tricking her. Yuuko visits Nano's home but Nano freaks out as she doesn't want her secret of being a robot exposed. Unfortunately, Hakase invites Yuuko in and reveals the truth about Nano and both of them quickly become friends much to Nano's horror. When Yuuko finally goes home, she calmly explains to Nano that it doesn't matter if she's a robot or not, as she's still Nano.
Hakase finds a crow and gives it Sakamoto's scarf to allow it to speak (voiced by Daisuke Ono) much to Sakamoto's anger as Hakase is too focus on making jokes with the crow instead of returning the scarf. In one silent segment, Mio and Yuuko try to finish a house of cards but their attempts are almost ruined by a sleeping Nano and Mai's antics. Unfortunately for them, the cards are destroyed when a ceiling lamp falls on it. Ms. Nakamura plans to kidnap Nano again by luring her to a hole in the ground but Tsuyoshi falls into instead. Annaka runs to Mr. Takasaki for help but he is currently conflicted as Makoto has blackmail him to become the Igo-Soccer club's adviser or he will tell the school that he's in love with his older sister, Ms. Izumi. Feeling guilty for Tsuyoshi falling into her trap and shaving his Mohawk, Ms. Nakamura decides to go and help free him but when she finds Annaka and Mr. Takasaki trapped as well, she changes her mind and runs away. Yuuko has enough with Mai's jokes and antics so she decide she will no longer comment about it again, but the temptation is too much which after a series of jokes, Yuuko finally gives in.
Yuuko brings Mio to the reopened coffee shop hoping to see her become confused by trying to order coffee but runs away crying when she learns Mio understands the menu. Ms. Nakamura makes coffee with a stronger drug for Nano but accidentally drinks it. Misato scolds Koujirou for skipping cleaning duty but she blushes when he agrees to do it. Yuuko goes to meet Mai at a fast food restaurant in another town but due to a series of misunderstandings she is laughed by a little girl who happens to be Misato's younger sister Mihoshi, who turns out to be also meeting Misato at the same restaurant. When Yuuko finally meets up with Mai, she is shocked to see Mai in a knight costume and wants to go trick or treating despite Halloween being over a week ago. Hakase shows off a robot powered by biscuits called "Biscuit 2" to Nano and Sakamoto but neither of them find it surprising. Yuuko has another 'Fey Kingdom' dream that reveals how Mio got her fuzzy pigtails.
While Misato, Weboshii and Fe-chan are waiting during a rain, Fe-chan decides to entertain the others only to get herself wet and dirty. Yuuko tries to help Mio perform a high jump correctly which the latter succeeds after she accidentally headbutts Yuuko, who in turn does the same thing to Mio in retaliation, pushing her over the bar. Hakase tries to get the laundry after it starts to rain but accidentally drops it. When she tries to blame the whole thing on Sakamoto, Nano decides to "punish" her and make no dinner for Hakase which the latter quickly admits the truth. Mio and Mai learns from Yuuko that they forgot to do their assignments but are forced to seek shelter at a Shinto shrine after it rains, this begins a chain of bad luck happening to them eventually involving the shrine's priest. Kenzaburou and Yuria Sekiguchi referees an igo-soccer match between Makoto and Mr. Takasaki with his friend Ogi from the Go club explaining to the former two who realize what kind of club they have unfortunately joined.
Mio has Nano, Mai and Yuuko help her draw her Yaoi manga that she is submitting. Unfortunately, Nano is embarrassed over the Yaoi, Mai keeps drawing unnecessary things in the manga and Yuuko accidentally spilled ink on one of the pages and tries to unsuccessfully fix it. Meanwhile, Misato has a talk with her senpai Yoshino over her feelings but the latter wasn't listening and instead, gives Misato spicy crackers. Nano plays a game of hide and seek with Sakamoto and the Hakase but when neither of them can't find Hakase and decides to take a break, Hakase, scared that they won't find her, immediately comes out of her hiding place. Back at Mio's home, Mio loses her temper on Yuuko about how her friends aren't helpful in drawing her manga especially Yuuko, who instead of buying the papers she needs to draw her manga, bought drinks and made unfunny jokes. When Yuuko tries to explain something, Mio continues shouting at her until she realizes that Yuuko did indeed buy the papers much to her embarrassment.
While Weboshii and Fe-chan hangout with Misato at her home, Weboshii tells her friends that she's interested with Tsuyoshi, believing he is a punk due to his Mohawk only for Fe-chan to reveal he isn't. While going out to town during the weekend, Mr. Takasaki incidentally meets Ms. Izumi shopping. Rather than take the chance to spend time with her, Mr. Takasaki becomes so focus on what to do next and runs away when Yuuko spots them. Ms. Nakamura decides to stalk and capture Nano by waiting at the supermarket she frequents. However, Mr. Takasaki spots her and comment how cute she looks in casual clothes which she runs away as the comment embarrass her throughout the day. In the Fey Kingdom airship, the minions manage to retrieve one of the wooden cubes but Mio sneaks in the airship to take the cube back and kill the minions due to the cube's power. As the minions helplessly face Mio's wrath, one of them manages to push her out of the airship where she lands back to earth and ending Yuuko's dream.
Tsuyoshi goes to the Shinto shrine to disprove exorcism by faking being possessed but when the priest gives logical conclusions for his problems, Tsuyoshi goes too far in his act which angers the priest after the former damages the shrine. Later, Tsuyoshi tries to escape working as his father's daifuku mascot but his father anticipated it so he put paint inside the daifuku mask, but to his father's shock, Tsuyoshi forcefully pulls it out, ripping his hair in the process. Yoshino encounters Mihoshi, who the latter does not like the former due to being naturally talented in Kendo. When Yoshino is distracted petting Sakamoto, Mihoshi tries to sneak attack her but instead hit the one person she wanted to beat, her Kendo assistant instructor. Fe-chan tries to give a positive outlook when Weboshii's meatbun falls on the ground, but when her popsicle also falls leading to series of accidents on her, Fe-chan throws a tantrum while Weboshii comforts her. Hakase drags Sakamoto out for a walk while Nano is waiting for her friends at home. However, Hakase and Sakamoto encounter Mai and her dogs but get trapped by the dogs when Mai suddenly disappears. Thankfully, Yuuko and Mio arrive and calm Hakase by saying the dogs are harmless, except the dogs bite them both. When Mai returns, she apologizes to Hakase by giving her chocolate. Hakase and Sakamoto then run away when two new dogs arrive at the scene. The dogs, Buddy and Kobuddy, actually came to pet and comfort Yuuko and Mio over what happened.
Yoshino has Mio taste her homemade jam which Mio finds disgusting and learns that it's made from fermented salt-cured fish. Ms. Sakurai finds a dirty magazine in Makoto's room which leads to an embarrassing and awkward argument between the siblings. Later Makoto brings Mr. Takasaki to the Igo-Soccer Club to be their club adviser but when Makoto mistakenly assumes Kenzaburou and Yuria are having intimate time together, Mr. Takasaki uses this chance to escape but comes back and agrees to be the club's adviser after Makoto bribes him with a photo of his sister in high school. At the same time, Weboshii decides to confess her feeling to Tsuyoshi with Fe-chan tagging along but when the girls finally see him, they are dumbfounded that Tsuyoshi is now bald. Mai visit Nano at her home but Hakase doesn't like her as she's still upset over the incident with Mai's dogs. As Mai tries to win over Hakase, she finally succeeds after drawing pictures of sharks for Hakase.
Yuuko catches Koujirou helping Nano and tells Mio. At first it seems Mio is unfazed but then she starts questioning Yuuko what were the two were talking about. But when Mio calls Yuuko an idiot after learning nothing happen between them, Yuuko takes revenge by lying that Koujirou was kissing Nano much to Mio's shock, after which Mio has a wild fantasy involving Nano and Koujirou. As the Tachibana sisters go home after Kendo practice, both sisters are surprise when Misato learns Koujirou has been attending Kendo classes and Mihoshi finds out that Koujirou is in the Acting club and not the Kendo club. Mihoshi decides to tease her sister by telling her to confess to Koujirou only to be shot by a bazooka by a flustered Misato. When Sakamoto gets sick and Nano taking care of him, Hakase pretends to be sick as well to get the same treatment but Nano refuses as she knows Hakase is lying which the latter throws a tantrum that Nano plays favorites with Sakamoto. While buying drinks for her friends, Mio encounters Koujirou picking up her coin but she is too embarrass to speak to him which Koujirou uses Mio's coin to buy a drink at the vending machine only for the machine to malfunction. Later that night, both Misato and Mio have thoughts about their feelings for Koujirou.
Misato wakes Koujirou to go to their next class and in her embarrassment, accidentally smashes his glasses. Despite that, Koujirou is more concern on the cuts on her hand. Feeling responsible, Misato decdies to walk hand in hand with Koujirou to class where they are seen by everyone but she shoots him with rocket launchers when she learns the glasses were for show. However, Mio catches the two together which shocks her and she runs away crying which Yuuko chases after her while Nano calls for Ms. Izumi and Mai for help. As Yuuko chases Mio running throughout town, Mio finally stops after rescuing a boy drowning and gets thanked by the boy and his friend, the police officer she knocked out before and an old man who was impressed with her shadow boxing which she finally calms down. Meanwhile, Ms. Nakamura chases after Nano when the latter, Ms. Izumi and Mai were looking for Mio but gets lost but luckily ends up at Nano's home. Nano invites Ms. Nakamura inside but the latter suspect it's a trap so she immediately tells Nano that she wants to know more about her which Nano misunderstands, thinking Ms. Nakamura wants to have a relationship with her. But when Ms. Nakamura is shocked to see Nano's creator Hakase and Sakamoto, who's upper body is trapped in a bag (which she thinks is a Homunculus), Ms. Nakamura tries to escape only to get caught in a puddle of glue. Later, Yuuko, Mai and Nano are worried that Mio has yet to get over her heartbreak so they poorly disguise themselves as daifuku mascots running a lucky draw and give Mio a prize; a voucher for a life-long friendship with Yuuko, Mai and Nano. Mio is touched by this and is glad to have them as friends.
Yuuko suggests throwing a surprise birthday party for Nano today which Mai and Mio agree which at the same time, Hakase has made a smaller wind-up key for Nano only for Sakamoto to accidentally crush it but Hakase promises to make a new one once she comes back from school. At school, the Principal is shocked to see his statue replaced by the Vice-Principal's own statue but his plot is exposed when the movers reveals they still have the Principal's statue and called the Vice-Principal's statue ugly. After Yuuko avoid several accidents with her friends and unintentionally help others, she tells Nano that she, Mai and Mio will be coming to her home as the three are holding the surprise party there. Ms. Nakamura finally finds her pet cat Taisho, who is actually Sakamoto, who is horrified to see his old owner due to how bad she was in taking care of him and manages to escape after Ms. Nakamura meets Nano and tells her to find and return Taisho if she ever finds him. When Nano returns home, Hakase removes Nano's wind-up key, revealing anyone can pull out the key except Nano herself, as she finishes the smaller one. As Yuuko, Mai and Mio arrives, Nano, after some thought, decides to keep the wind-up key after realizing that her friends still treat her the same no matter if she's a robot or a normal girl. As everyone celebrates Nano's birthday which coincidentally was today, Nano learns to her chagrin that the smaller wind-up key was actually an add-on that makes her wind-up key spin when she's happy. Despite that and having two ruined birthday cakes, everyone has a good time at the party. In this episode, Nano actually wins against Hakase in a game of "rock, paper, scissors." Although, Sakamoto covers her eyes, so Hakase can't see what's happening.