|Release Date||November 28, 2018|
|Opening Theme||Kimi no Sei|
|Ending Theme||Fukashigi no Karte|
|Episode 8||Episode 10|
After a no-dating rule is imposed by her management, Mai is too busy with work to spend any time with Sakuta. As he excitedly welcomes the start of the second trimester and the opportunity to see Mai at school, Sakuta is shocked to be asked “who are you?” when he runs into Mai in front of his house. Upon looking into the situation, he discovers that Mai and her little sister, Nodoka Toyohama, have switched bodies. Until they can resolve this case of the “Puberty Syndrome,” Mai must spend her days as Nodoka and Nodaka must spend her days as Mai...
As the day continues on, Sakuta learns that Nodoka is Mai's half sister from her father's side. The next day, Sakuta learns that both Mai and Nodoka's mothers are against each other due to their ex-husbands. With this in mind, the two mothers use Nodoka and Mai as the "pawns of the proxy war". Later in the day, Sakuta and Rio discuss about how Nodoka's envy against her sister might have caused the syndrome to activate. Knowing this information, Nodoka and Sakuta visit the ocean. At there, Sakuta confronts Nodoka about how she truly feels about her sister. He talks to her about why she talks to her so politly, and figures out the true feeling Nodoka bares about her sister. The next day, Sakuta witnesses Nodoka passing out in a photoshoot. Sakuta later informs Mai about this issue, for him to witness Mai expressing shock on her face. Sakuta later receives a key from Mai, and he visits Nodoka and the messy home she lives in. In there, Sakuta decides to cook for Nodoka, noticing the poor conditions she has lived in. The episode ends with Sakuta about to open a cabinet.