Naota's older brother went to the U.S. to play baseball, and his brother's girlfriend is making advances on him. There's a so-called alien girl hitting on him, too. With a guitar. Did we mention the robots keep springing from Naota's head?

Hanging out by the river, no one would suspect Mamimi is a girl with a dark past. She's been obsessed with a videogame. There's been a string of fires around town. If that's not enough, there's something growing inside Naota's head.

With a robot and an alien at home, Naota tries to at least have a normal school life. The class is putting on a play, and Naota is playing a cat. He's sprouted cat ears from his head. Class president Ninamori's been chosen to play the lead.

Though he's carried around his brother's bat, Naota has never hit anything. Now his brother's gone, it's Naota's turn to prove his worth. The baseball team doesn't seem to be doing so well. What is Haruko doing playing for the other team?

Mabase is safe for now, but there's a new kind of danger. Naota finds himself in the midst of a survival game, with Haruko on his team. With weapons blazing, it looks like Kitsurubami has joined the fray. Amarao is getting his hair dyed?

The end is near with both Haruko and Canti at large. Medical Mechanica is preparing to move. Before Amarao can do anything to stop it, he needs to find the terminal core. Mamimi has found new friends with an appetite for the mechanical.