This Art Club Has a Problem!

Mizuki tries to do well in her school's Art Club, but she seems to be the only person focusing on her art. The club president does nothing but sleep in the room, and her clubmate Subaru only creates "2D wives" with his time, frustrating Mizuki to no end. After Subaru asks Mizuki to pose for him, his painting only uses the same panties she wore, ignoring her pose and likeness entirely, though he secretly sketches her pose afterwards. Later, Subaru plans to quit the club after finalizing his "perfect wife", leading Mizuki to tearfully try to beg him not to leave. When she composes herself the next day, Subaru is moved enough by Mizuki's actions that he decides to set his previous art aside and work on a new 2D wife, inspired by Mizuki's crying.

After accidentally knocking over one of Mizuki's paintings into a puddle of red paint, the President tries to cover it up, but Mizuki quickly sees through the ruse. The club is forced to submit one of Subaru's painting's for a contest instead, which ends up winning second place. Later, at a sleepover, Mizuki flashes back to when Subaru was able to quickly sketch a missing girl's mother from memory to reunite the girl with her mother. The next day, Subaru asks Mizuki for advice on rejecting a love letter, as he only loves "2D girls." On the way home from school, Subaru appears to be attracted to an elementary-school girl, but turns out to be only interested in the character strap on her bag.

Subaru finds Colette, the youngest member of art club, in the clubroom looking for a locket with a "precious photo" in it. She turns out to have left it in her pocket the whole time. Subaru has trouble painting the perfect hairstyle for his latest "wife" and Mizuki suggests a "short bob" - her own hairstyle - while Colette mishears it as "Shō to Bob" and draws two guys named Shō and Bob. The next day after school, Mizuki's friends - Kaori, Sayaka, and Ryōko - come to look at the Art Club's room. The three decide to do a drawing contest where the loser with the ugliest art has to buy drinks and that person is Kaori. Kaori offers Subaru her drink, but Mizuki snatches it and drinks it out of jealousy. Subaru decides to drink Mizuki's soda instead.

Yumeko is handed the faculty advisor position for the Art Club. Though Yumeko is frightened of the club members' various quirks at first, she lets Subaru and Mizuki draw a quick picture of her. One day, Colette plays a game where she tries to stay in the shadows outside. She passes the game on to a little girl, who happens to be interested in art herself after past events ("Good Child Poor Child Lost Child"). Subaru comes over to Mizuki's house at night to give her missing homework papers. Mizuki tries to work up the courage to ask him for his contact info. Meanwhile, Mizuki's mom lurks nearby, spying on their relationship.

When she is alone in the room, Colette paints over a model head, but goes too far and flees. This action sets off a series of miscues: Yumeko faints after seeing what she thinks is a real head in a box, Subaru tries to give Yumeko mouth-to-mouth resuscitation while reluctant to do so with a 3D woman, the President spots the two and thinks they are making out, and finally Mizuki gets help from a teacher before Colette confesses to what really happened. One day, the Art Club is assigned to clean the school's pool. The President suggests painting a picture on the pool surface before rinsing it away. After taking a photo of their work, the club discovers that the President accidentally bought oil-based paint that does not wash off.

A new girl named Maria Imari transfers into Subaru's class. Mizuki suddenly finds herself fighting with Maria for Subaru's attentions, as Maria seems to have very similar hobbies and interests to Subaru. On the way back from the bookstore, Subaru, Mizuki and Maria help retrieve a balloon from a tree for a sad child. Mizuki wonders if she can co-exist with this new rival.

Yumeko enrolls the Art Club in a regional competition. After a classmate insults the Art Club's previous entry ("The Murder Case of Art Club's President"), Mizuki declares that her club will win the contest with another of Subaru's paintings. On the day of the exhibition, Subaru's drawing wins first prize, while the classmate's entry does not even earn a spot. Colette declares that she wants to be a "Hero of Justice" when she graduates school, but no one takes her seriously. As she runs to the roof, she stumbles across Maria, who is acting out an original fantasy. Colette becomes drawn into her world, and shows up the next day wearing similar costume.

While everyone is doing their usual club work, Mizuki is the only one who can't concentrate due to the painted head (from "Mistake Train"), hence they look for a new thing to act as a model. The President states that there might be an old plaster figure in the art club storage room next door. Mizuki and Subaru look together, and they instantly get preoccupied by the things in the store. Before they knew it, the door can't be opened (it was broken somehow), and they spent time together in the room for a couple of hours, until they found out that there is a door connecting the club room and the storage room. In the end, the old plaster figure they found is also painted, probably by the past club members. After the founding of the storage room, Subaru and Maria spend time together in the store reading manga together, to Mizuki's dismay. Suddenly, Maria found a riddle for treasure in one of the manga by the past art club members, so they start looking for it. It turns out to be a porn magazine.

Maria tells Colette that she is looking for "Necronomicon", a dangerous magical grimoire. Due to a misunderstanding, Yumeko also join in the search. Meanwhile, the President wants the porn magazine (from "Let's Treasure Hunt") for himself. When Yumeko enters the clubroom, she mistakenly said the grimoire's name, and the President thought she meant "Nekomi Lock On", which is written in the front cover of the magazine. This forces Mizuki and Subaru to hide the book in Subaru's shirt, as they try to make it out of the school. Colette and Maria found them acting suspiciously, and Colette thought Subaru has the "Necronomicon", and snatch it from him after a struggle. Unluckily, Yumeko walks in at the worst time possible; and after confirming that Subaru had the book previously, Subaru is asked to meet with her at the teacher's lounge for punishment. Subaru meets the challenger (from "Our First Joint Task...?") again, and they compete to a drawing, with Mizuki as the model. Infatuated with Mizuki's cuteness, the challenger ends up drawing nothing and lost the contest. Moeka, the girl that Subaru and Mizuki helped before ("Good Child Poor Child Lost Child") found the President ditching class at school, and he ends up playing with her the game from before ("Colette's Walk"), winter version (now they can't step on shadows), while bringing her to the teacher's lounge to look for her grandfather, who turns out to be Yukio, the previous art club's adviser.

Last year, right after they helped Moeka ("Good Child Poor Child Lost Child"), Mizuki and Subaru's popularity rises in school. Being a newbie, Subaru can't remember where they put the spare blue paint, thus Mizuki has to point it to him. It's also the first time Mizuki meets Sayaka Honda, a member of newspaper club, who wants to interview them about the lost child case. On the other hand, Takeda signs Mizuki up for Student Council election, with Mizuki having trouble to decline him. After hearing what Mizuki said about him during the interview from Sayaka, Subaru helps her to make a refusal. After a year, Subaru is still having trouble finding spare paints. Subaru and Colette gets poor mark on the last exam (Subaru had 30 episodes of anime to watch each week, thus he can't focus), angering Yumeko. All four Art Club members end up study at Mizuki's house (though the President sleeps all the time). Subaru and Colette ends up sleeping next to each other on Mizuki's bed, angering her. Though, the study ends well, and both Colette and Subaru get good results. Kaori, under the suspicion of Maria going to snatch Subaru from Mizuki, tails her throughout the day, but ultimately fail. Instead, she is treated well by Maria, and her perception of Maria drastically change on the next day.

Hearing from Yukio that Art Club only focuses on competition and not cultural festival, Yumeko wants them to contribute something for cultural festival. Getting inspired from the empty cans people throw out, she decides that the Art Club should make tin can art, and she reserved the gym for display. Subaru suggests to make a waifu, while Colette suggest a hero (both denied by Mizuki), so Mizuki thinks of the design on her own. They end up making a sculpture of paint tube, with some paint spilling out (suggested by Maria). Problem arises when Moroboshi-sensei misunderstood Maria's chuuni-like expression and thought the cans are to be thrown out. The President suggested that they buy can drinks from outside and sell in at the school in order to fit the theme (Made in School). Mizuki feels irritated when Maria said the costume is tight on the chest and attracts a lot of attention due to her charm. The art challenger ("Our First Joint Task...?" & "The Challenger Returns") returns; this time having a drink match with Subaru. He ultimately lost when he saw Yumeko in a panda-cat costume and spills her drink out of his mouth unto Subaru. Mizuki (unknowingly) rubs salt to the wound by wiping the spilled water from Subaru. When the art is finally ready and done, the President points out that it is too big to fit on the door, thus they need to dismantle it once more.

It's raining outside and Mizuki has some stacks of books that a teacher asked her to carry, while Subaru walks by. As she is done dropping off the books, Subaru meets her by the entrance of the school. Earlier when Maria was around she is standing outside in the rain, Subaru wonders why she is there, just being out and could of caught a cold. When he asks her to go back inside of the school. Then Mizuki and Subaru shares an umbrella going home. Later everyone is thinking about the future and Mizuki went by Art Club to look at something before anyone like the President or even Subaru is there too. Then Subaru walks in and tells that he likes a character from an anime, that Mizuki overheard with Maria, then leaves. Not long as Subaru said it, Mizuki says she likes Subaru and was interrupted by that. As the door was closed the President pops up from hiding out and reminding that school life is short. The next day Subaru and Mizuki walks to school and the wind blows on Mizuki's hair, when Subaru felt gloomy about something, and told that the character from the anime had a boyfriend while watching one of the episodes.