Posing as Mitsuki Sanada’s brother at school, Kazuki is overwhelmed by male students vying for her attention, leading to tension when he accepts their love letters. Mitsuki, annoyed, assigns him to respond to each one. When D moves into their home, Mitsuki builds a wall to separate her from Kazuki, frustrated by D’s preference for his instructions. A mix-up with Mitsuki’s diary escalates tensions, but a rainy search brings them closer. Yayoi’s arrival as their neighbor complicates their daily routine, testing their group dynamic.
Kazuki experiences hallucinations of fighting robots that no one else can see, so he should have expected trouble when the most beautiful girl in school took an interest! But there's no way he could have expected to be waylaid by a mad scientist and thrown into a parallel world with robots, aliens, and a boarding house filled with beautiful girls! He may not make it home. He may get hurt. He may go insane. But at least he gets to drive the Robots!
