High schooler Ganta Nakami struggles to sleep at night, making him restless and irritable during the day. Seeking solace in secluded spots to nap, he crosses paths with Isaki Magari, a popular girl hiding her own sleep troubles. Magari invites Nakami to share her hidden sanctuary in the school's old astronomy club observatory. Together, they find comfort in each other's understanding, easing their individual challenges as they navigate the complexities of their shared condition.