Takanashi spends some quality time with his four quirky sisters; the boss, the drunk, the writer and the manipulative. Each in their own way is reliant on Takanashi to keep their family in order. White Day has arrived and Takanashi gifts Mahiru a bag of hair pins. This is the first White Day gift she has ever received. Later he runs into her on the street worried that she might attack some random male while walking around he escorts her home. On the way they run into his eldest sister Kazue. Mahiru get flustered and admits to "assaulting" Takanashi on a regular basis.

Popura becomes upset with Sota constantly calling her small. Later, Sota becomes devastated when Kyoko kills a bug, inadvertently insulting Popura and Inami in the process.

Aoi becomes curious about Hiroomi's secret life and drags Popura into stalking him, despite the fact he is completely aware of it. Later, Popura tries to get Sota to treat Mahiru nicer. Tired of Jun's teasing, Popura tries to get revenge on him which does not go to plan. Meanwhile, Aoi acts very clingy around Otoo after he comes back from his recent trip.

Popura and Jun end up catching colds due to Aoi's clumsiness, so Kyōko calls in two of her juniors, Yohei and Mitsuki Mashiba, twin siblings who don't get along. When Kyōko offers to put someone else in charge of looking after Inami, Sōta becomes upset and falls out with Inami, but Inami soon manages to build up the courage to make up with him.

Sōta becomes depressed when he discovers Nazuna has grown as tall as him and has Popura act like his little sister for the day. Mahiru becomes jealous of this and works with Hiroomi to try and get Sōta to call her cute. The next day, Kirio comes to Wagnaria to look for his sister, but finds himself coming into conflict with the men, whilst Hiroomi attempts to keep him and Aoi from meeting each other.

Jun takes Yachiyo to buy a cellphone, whilst Kozue takes a liking to Yohei. Meanwhile, Mitsuki becomes suspicious of Jun's familiarity with Yachiyo whilst Yamada runs away after Sōta scolds her.