Kana arrives late to breakfast but demands more rice,irritating Chiaki and Haruka. Haruka reluctantly gives her seconds before Kana rushes to school. At school, Haruka’s classmates nominate her as the new class leader against her wishes. Atsuko recalls the Legend of the Banchou, a story about Haruka’s supposed delinquent past, and shares it with Maki. At Chiaki’s school, students discover a hamster in an Amazon.co.jp parody box. Chiaki takes charge after Uchida tries to feed the hamster a pencil. She orders Uchida and Makoto to buy supplies, and Touma accidentally volunteers to become the hamster’s official caretaker. At home, Chiaki announces her new responsibility. She claims experience caring for animals while staring at Kana, implying Kana herself requires animal-like handling. Haruka receives a suspicious phone call mentioning the Banchou. The next day, Yuu and Hiroko visit Kana’s classroom, having heard rumors of the Legendary Banchou’s return. Kana misinterprets Haruka’s phone call and believes Haruka has resumed her Banchou role. Kana summons Fujioka to the roof and declares him the Banchou of their school as Haruka’s right hand. She later orders him to clean glass outside the school, believing Haruka once smashed all the windows. A classmate corrects her that Haruka actually cleaned the glass. Frustrated, Kana considers becoming Banchou herself. At home, Chiaki and Kana spy on Haruka slicing vegetables with intimidating precision, convincing Chiaki that Haruka might truly be a Banchou. Chiaki reviews her classmates and finds none worthy of serving in a Banchou army, so she apologizes remotely to Haruka for being unable to support her. Haruka returns home, rejects the class leader position, and clarifies she never was a Banchou. Chiaki punches Kana as punishment for starting the rumor. The next day, Kana cancels the Banchou army plans and reinstates Fujioka as Banchou, though Fujioka remains confused about his role.

Chiaki's classmates invite themselves to the Minami home for a group homework session and a sleepover. Kana declares the event a pajama festival and appoints herself head of hospitality,which annoys Chiaki. Haruka agrees to host the gathering on the same night and decides to prepare a family-style nabe meal for the guests. Chiaki secretly invites Fujioka to dinner, hoping his presence will distract Kana from interfering. Makoto arrives dressed as Mako-chan, but Kana pulls him aside and orders him to change back into his normal clothes. The new neighbor, a boy named Fuyuki, comes to the door with a gift, but he declines Haruka's invitation to join the meal. After eating, Kana lies on the floor with her stomach exposed, and Haruka warns her to cover herself in front of Fujioka. While Chiaki and her female friends bathe, Kana attempts to serve them milk but gets thrown out for making inappropriate comments. Later, the girls gather in Chiaki's room to talk about romance, and Kana takes over the conversation. She pulls the room divider shut, leaving Chiaki alone on her side because she considers Chiaki underdeveloped compared to the others. The next morning, everyone gathers at the kotatsu, and Haruka asks whether they completed their homework. No one answers.

Haruka encounters a boy named Fuyuki while taking out the trash. Neighbors praise Fuyuki for his volunteer work on weekend neighborhood cleanups. Haruka returns home and finds Kana and Chiaki still in bed after their alarm fails. She inspects their messy room and their indifferent attitude toward cleaning it. Haruka informs her younger sisters that they will participate in the weekend neighborhood cleanup. At school,Chiaki recruits Uchida and Yoshino to help. Kana invites Fujioka and Keiko without explaining the actual work. On cleanup day, Hosaka, Touma, Maki, and Makoto also appear. Kana lies on a park bench instead of working. Haruka threatens Kana and Chiaki with no dinner if they do not work. Kana rallies the group to collect more trash than Fuyuki. She finds an abandoned refrigerator and struggles to open it. The group speculates about cash or a body inside. Kana opens the door and finds only medium-sized rocks. She and others throw rocks into the river as snow begins to fall. Haruka catches them and enforces the no-dinner punishment despite their excuses. Chiaki tells Fuyuki he should refuse requests when he does not want to comply. The next morning, Haruka finds Chiaki and Kana already at the breakfast table, desperate for food.

Haruka leaves Kana and Chiaki at home while she goes out with Maki. Kana searches the kitchen drawers for food and discovers a small locked chest. Unable to open it alone,Kana convinces Chiaki to help by suggesting the chest contains naked baby pictures of Chiaki. The two sisters break open the chest and find a glass rabbit necklace inside. Kana accidentally steps on the necklace, breaking off one ear. When she tries to repair the ear, she breaks off the other ear, the tail, and finally the head. Chiaki attempts to glue the pieces back together. Kana mobilizes Fujioka, Keiko, Yoshino, Touma, and Uchida to search for an identical replacement glass rabbit. Kana and Chiaki stall Haruka after she returns home, keeping her away from the kitchen. Keiko calls the house with a report on her search, revealing Kana's scheme to Haruka. Haruka enters the kitchen to find the damaged necklace. Kana fails to find a replacement anywhere. She returns home to a darkened house, where Chiaki sits crying in the entryway and Haruka waits at the end of the hallway.

Kana borrows an entire manga series from the neighbor Fuyuki and comments on his polite use of formal speech. Snow falls outside,and Haruka returns home to find the refrigerator nearly empty. The three sisters eat a simple meal and discuss errands for the following day. They go outside to play in the snow before returning to take a bath together. Kana opens the bathroom window because the hot water makes the room too warm. After the bath, the family sits under the kotatsu when a power outage plunges the apartment into darkness. They light a single candle and huddle together under blankets to stay warm. Kana decides to take a second bath, but the water has turned cold because she left the window open. Hungry and without fuel for the portable stove, Kana complains about how long the electric company is taking to restore power. Haruka suggests checking on Fuyuki, and the sisters find him reluctant to admit he wants company. Chiaki chastises Fuyuki for hiding his true feelings, and the argument escalates into a snowball fight. Fuyuki agrees to spend the night, but the next morning he leaves early to shovel the complex sidewalk alone, leaving Chiaki visibly annoyed.

Valentine's Day arrives,and the Minami sisters make chocolates at home under Haruka's instruction. Kana turns the activity into a small festival by inviting Touma, Yoshino, Uchida, and Makoto, who appears as Mako-chan. Kana forces Makoto into a maid costume to stay over, much to Uchida's amusement. Kana eats more chocolate than she prepares and raids the refrigerator for cooling chocolate, taking the batch that Chiaki spiked as a trap. Haruka asks each girl who will receive their chocolates; Mako-chan names Haruka, then reluctantly says "Makoto-kun" when pressed for a boy's name. Kana plans to give away no chocolate and instead consume whatever she can find. At the middle school, Fujioka receives many chocolates from other girls but hides them, hoping Kana will give him chocolate instead. Kana arrives seeking chocolate from him, not offering any, and later consults Keiko on which boy receives the most chocolate. Kana collects a large pile of chocolate and gives one piece to Fujioka, assuming his empty-handed appearance means he received none. At home, Haruka gives chocolate to both younger sisters; Chiaki gives a chocolate back to Haruka, insisting no boy compares to her sister. Kana steals the chocolate Haruka gave Chiaki, and the two sisters break into a fight.

A shopkeeper gives Haruka tickets to a new pool and hot spring resort. Kana invites her friends for a Saturday trip,while Chiaki secretly worries because she cannot swim. Chiaki researches swimming online but quickly hides the screen when Kana enters, and Kana teases her about visiting porn sites. At school, Uchida and Yoshino show excitement about the trip, while Makoto, in his Mako-chan disguise, asks Touma for advice on whether to attend. Fujioka also receives pool tickets and invites Kana, who tells him to come to her house Saturday morning. On the day of the trip, Fujioka arrives only to find a large group, including the Minami sisters and their friends, and his hopes for time alone with Kana vanish. The girls wear swimsuits under their winter clothes, and Touma has selected a swimsuit that hides Makoto's true gender. Takeru drives the group but gets lost on the way, and during the drive he questions Fujioka about his relationship with Kana. At the pool, Kana discovers Chiaki's inability to swim and teases her, then offers to help but repeatedly lets go whenever Chiaki complains. Fujioka rescues Chiaki during one of her panicked moments. Meanwhile, Hayami holds a volleyball club meeting at the same resort, so Maki and Atsuko attend while Haruka sleeps nearby, and Hayami and Maki eventually throw the sleeping Haruka into the pool. Kana ends the day by inviting everyone, including Haruka's friends, to gather at her apartment afterward.

The Minami sisters eat sukiyaki for dinner. Kana claims she dreamed about the meal the previous night and declares herself psychic. She vows to prove her ability by predicting the next day's dinner. Kana later has a strange dream featuring Chiaki eating carrot sticks. At school,a teacher asks Haruka to consider joining the Overseas Exchange Program, a request that visibly depresses her. Meanwhile, Makoto accepts an invitation to study at the Minami residence as himself. Kana punches Makoto when he taunts her, causing him to fall and look up Chiaki's skirt. Chiaki orders Makoto to leave, but Kana gives Uchida a bag of girls' clothing. Makoto changes outside and returns as Mako-chan. Yoshino's probing questions make Makoto fear exposure, so he flees the apartment. Chiaki asks Haruka if she has changed, and Haruka confirms that friends influence people. At dinner, Haruka serves crab legs, and Kana realizes her dream came true—the orange items were crab legs, not carrot sticks. She chooses to remain silent. The next morning, Chiaki appears with a new hairstyle featuring two hair bobs. Hosaka argues with Hayami over a bento lunch; Hayami slaps and kicks him after he tries to reclaim the bento she took. Hosaka concludes that he is delicious regardless of the situation and remains devoted to Haruka. The episode closes with Chiaki visibly changed and Kana keeping her successful prediction a secret, while Haruka continues to grapple with the study abroad decision.

Fujioka visits the Minami residence to check on Kana after she fakes illness to avoid classroom cleaning duties. He finds Touma in the living room wearing a girls' school uniform,but Fujioka still believes Touma is a boy. Touma flees to the bathroom in embarrassment. Kana tries to cover for the situation by chasing Fujioka around the house and attempting to force him into her own uniform, claiming everyone must cross-dress that day. Fujioka refuses and leaves. Later, Kana fakes a cold to avoid participating in the neighborhood cleanup. Haruka leaves Chiaki at home to monitor Kana and gives Kana a bell to ring if she needs anything. Kana repeatedly rings the bell to make Chiaki fetch drinks and manga, treating her like a servant. Chiaki grows suspicious of Kana's behavior and eventually accuses her of faking, striking Kana with a plush toy. The next morning, Chiaki wakes Kana for a planned shopping trip and all-you-can-eat rib dinner. Kana gets out of bed and discovers she has actually caught a real cold. She tells her sisters to go without her, claiming she needs to do homework. Uchida and Mako-chan arrive at the apartment with medicine and cold remedies. Kana attempts to recover before Haruka and Chiaki return home, but her condition worsens. Chiaki quickly figures out that Kana is genuinely ill once she and Haruka return. Kana then seeks Chiaki's advice about Fujioka addressing her only as "Minami" while using her sisters' first names. Chiaki instructs Kana to demand Fujioka call her "Kana-chan" and then attack him when distracted. Kana executes the plan at school, grabbing Fujioka from behind for a wrestling move, but the move fails and instead becomes a hug that leaves Fujioka blissfully happy.

Chiaki visits the school nurse,Kumada-sensei, after feeling warm. Kumada-sensei inflates Chiaki's temperature reading twice to keep her in the office. The nurse asks Chiaki to tell her homeroom teacher, Tanaka-sensei, that Kumada-sensei remains single. Chiaki declines the request and also refuses a ramune candy. Makoto arrives feeling ill, and Kumada-sensei gives him the same candy as medicine, which immediately improves his condition. At the school athletic fair, Chiaki works on the first-aid committee. Touma tries to offload her paper flower duties onto Fuyuki-kun, but Chiaki intervenes and insists they all work together. After multiple attempts to speak with Chiaki outside their apartments, Fuyuki-kun fails to express what he intends. During the scavenger hunt, Chiaki grabs Fujioka because her slip of paper reads "father." Fuyuki-kun selects Kana as his partner because his paper reads "older sister." At lunch, Chiaki finds Fuyuki-kun eating alone and invites him to join her family. Fuyuki-kun admits this is his first time sharing a meal with others. After the fair ends, Chiaki learns that Fuyuki-kun transferred to another school with his father. She returns home alone, imagining him opening the door to his former apartment. Days later, Maki and Atsuko discuss Haruka being selected for the overseas study program. Kana overhears their conversation from outside the restaurant, shocked that she has not heard this news from Haruka.

Kana overhears from Haruka's friends that Haruka plans to study abroad. She shares the news with Chiaki,who wants to confront Haruka immediately, but Kana persuades her to stay silent. The next day at school, Chiaki discovers her classmates already know about Haruka's departure and support the decision. Kana gathers Chiaki, Yoshino, Uchida, Makoto, and Touma to execute a plan. She wants to prove that she and Chiaki can handle cooking and cleaning so Haruka can leave without worry. While Haruka attends a volleyball club event, the group takes over the kitchen. Makoto and Touma volunteer as food tasters. Chiaki, Uchida, and Yoshino prepare ingredients under Yoshino's supervision. Their first attempts at making hamburger steak patties fail repeatedly, and the tasters fall ill from the results. Chiaki and Yoshino eventually discover the correct preparation method, and the patties turn out properly. The following morning, Chiaki and Kana wake early to vacuum, clean, and do laundry before Haruka gets up. They prepare lunch and present Haruka with hamburger steak. Haruka eats it and praises their cooking. Chiaki breaks down crying and begs Haruka not to leave the country. Kana initially resists showing emotion but joins Chiaki in pleading for Haruka to stay. Haruka explains that she never intended to study abroad, and the rumor started from a misunderstanding. The episode closes with the sisters' daily life continuing unchanged.