Class of Brains

All of his peers, comprising his closest friend and his romantic interest, have been transformed into mere brains. An extraterrestrial entity known as A-sensei informs the protagonist, Satoki Tsutsuno, that in order to safeguard the planet, they must harness their combined intellect. With Tsutsuno as the sole survivor in his class, what challenges lie ahead for him and his fellow classmates...?