Insomnia becomes the language two people use to tell each other they're not alone. There's no grand confession, no orchestral swell, just two teenagers learning that sometimes the quietest moments with another person are the ones that save your life. The romance here is built on the radical act of showing up, consistently, for someone else's broken sleep, and by extension, their broken self.

Ganta Nakami can't sleep. His insomnia leaves him irritable and cranky at school, where he is always looking for a quiet corner to nap. While gathering boxes for the school festival, he is sent to the abandoned astronomy club observatory and finds his classmate Isaki Magari asleep inside. Isaki is popular and well liked, but nobody knows she has insomnia too, and she has been using the observatory as her secret sleeping spot. Once they realize they share the same problem, she lets him share it. The two begin catching up on sleep there together, and in each other's company their struggles start to feel easier to face. The result is a gentle romance with a slice-of-life pace.