"Insomniacs After School" centers on two high school students, Ganta Nakami and Isaki Magari, who struggle with chronic insomnia. Their paths cross when they both seek refuge in the school’s abandoned observatory, a quiet space where they can escape the pressures of daily life. Nakami, a reserved and academically driven student, often feels isolated due to his inability to sleep, while Magari, a cheerful and outgoing classmate, hides her own struggles with insomnia behind a bright demeanor. The observatory becomes their shared sanctuary, fostering a unique bond as they navigate their sleepless nights together.

The narrative explores their growing friendship and mutual understanding as they support each other through their shared condition. Their interactions are marked by a blend of lighthearted moments and deeper emotional exchanges, as they discuss their fears, dreams, and the challenges of living with insomnia. The story delves into their personal lives, revealing how their condition affects their relationships with family, friends, and their own self-perception. Nakami’s introspective nature contrasts with Magari’s optimism, creating a dynamic that balances humor and introspection.

As the series progresses, the observatory becomes a symbol of their connection, and they begin to use it as a space to stargaze, further deepening their bond. The act of observing the night sky serves as a metaphor for their journey, highlighting themes of hope, resilience, and the search for meaning in the face of adversity. The story maintains a grounded tone, focusing on the characters’ emotional growth and the quiet moments that define their relationship. Through its exploration of insomnia and its impact on their lives, "Insomniacs After School" offers a heartfelt portrayal of two individuals finding solace and understanding in each other.