When Ganta Nakami goes into the observatory, rumored to be haunted, he finds his classmate Isaki Magari sound asleep! They learn they're both struggling with the same problem.
Ganta and Isaki have experienced lonely nights as they each struggle with sleeplessness. They form a "Nightly Fun Society" using the observatory as a secret base.
Despite starting a part-time job, Ganta hasn’t raised enough money for training camp. But thanks to Isaki staying at her grandmother's house, their problems are solved.
Isaki's parents find out that she and Ganta have been staying all by themselves. Naturally, they demand that Isaki come home right away, but she refuses.
