Makoto Niwa, meticulous in grading his life experiences, relocates to a new town to live with his aunt when his parents travel abroad. Expecting a typical adolescence, he is caught off guard by the sudden appearance of his mysterious long-lost cousin, Erio Touwa. Unlike him, she prefers cocooning herself in a futon and identifies as an alien. Makoto's vision of a normal life shatters as he encounters this eccentric cousin and other quirky girls in the neighborhood. Embracing the unconventional, Makoto realizes that an abnormal youth might just offer unexpected excitement.