Rascal Does Not Dream of a Sister Venturing Out

March begins, and there is only one month left in the third term. Sakuta Azusagawa is about to celebrate the graduation of his girlfriend Mai Sakurajima. As he waits for Mai at Shichirigahama beach, an elementary school-aged girl who looks like Mai did when she was a child actress appears in front of him. While reflecting on this mysterious encounter, he receives a phone call from his father. Kaede’s mother never came to terms with what happened to Kaede. Having been hospitalized for so long, their mother finally wants to see her daughter. To fulfill their mother’s wish, Sakuta makes the decision to meet face-to-face–something they haven’t done in a long time. He’s unable to hide his nervousness about all this. Never-before-seen scars begin to appear on Sakuta’s body. Could these be warning signs of a new type of puberty syndrome?

In Fujisawa, where the skies are bright and the seas glisten, Sakuta Azusagawa is in his second year of high school. His blissful days with his girlfriend and upperclassman, Mai Sakurajima, are interrupted with the appearance of his first crush, Shouko Makinohara. For reasons unknown, he encounters two Shouko's: one in middle school and another who has become an adult. As Sakuta finds himself helplessly living with the Shouko's, the adult Shouko leads him around by the nose, causing a huge rift in his relationship with Mai. In the midst of all of this, he discovers that the middle school Shouko is suffering from a grave illness and his scar begins to throb...

Theatrical follow-up to Seishun Buta Yarou wa Santa Claus no Yume wo Minai . "Actually, I’m Touko Kirishima." The audience erupted in excitement upon learning that the true identity of the mysterious, wildly popular internet singer was none other than the nation’s favorite actress, Mai Sakurajima. The scene was exactly the same as the dream Sakuta Azusagawa had seen on Christmas Eve. Starting with Mai’s shocking confession on April 1, the impossible events that everyone once dreamed of keep happening one after another. The social media hashtag "#Yumemiru," where dreams come true, has vanished, and as Sakuta struggles with the disconnect between the reality before him and his own perception, he receives a message from a version of himself in an alternate reality. ―Stop Touko Kirishima, ―Before reality is rewritten. To restore the world to its original state, Sakuta sets out to find Touko Kirishima. This is a story about overcoming the "Adolescent Syndrome".

There's a rumor about a mysterious phenomenon called "puberty syndrome." For example, Sakuta Azusagawa is a high school student who suddenly sees a bunny girl appear in front of him. The girl is actually a girl named Mai Sakurajima, who is Sakuta's upperclassman who is also a famous actress who has gone on hiatus from the entertainment industry. For some reason, the people around Mai cannot see her bunny-girl figure. Sakuta sets out to solve this mystery, and as he spends time with Mai, he learns her secret feelings. Other heroines who have "puberty syndrome" start to appear in front of Sakuta.