Makoto Niwa is a high school boy who, since his parents are away on business, lives with his aunt’s family. It is there he meets his mysterious cousin of the same age Erio Touwa—who happens to tie a futon around her upper body and is a self-proclaimed alien. Her staple food is pizza. Erio had been missing for half a year and was found floating in the sea. She doesn't remember anything about what happened during that period of time, but she began to think that it was the act of an alien and wanders the neighbourhood wrapped in the futon.
After winning a fierce battle against Yosen High, Seirin High basketball team successfully advanced on the semifinals of the Winter Cup. They continue aiming to become the champion but this makes hard for them since they're against powerful opponents.
Chihiro Furuya, who loves zombies above all else, meets the sweet girl Rea Sanka by chance, and he ropes her into "resurrecting" his dead cat. But then Rea claims she actually has become a zombie, and asks him to take responsibility for it.
Despite Ryuji Takasu's gentle personality, his eyes make him look like an intimidating delinquent. Class rearrangements on his second high school year put him together with his best friend, Yusaku Kitamura, and his hidden crush, Minori Kushieda. Along with these two comes Kushieda's best friend, Taiga Aisaka. Her delicate appearance contrasts with her brutal personality. Secretly in love with Kitamura, Taiga agrees to help Ryuji with his love interest as long as he helps her get closer to hers.