"Grisaia no Kajitsu" centers around Yuuji Kazami, a transfer student with a mysterious past, who enrolls at Mihama Academy, a secluded school for students carrying emotional or psychological burdens. The academy houses only five female students, each with deeply personal and traumatic histories. Yuuji’s arrival disrupts the fragile equilibrium of their lives, as his calm demeanor and sharp intellect draw the girls toward him, prompting them to confront their unresolved issues.

Amane Suou, the cheerful and motherly figure of the group, hides a tragic past tied to a bus accident that claimed the lives of her classmates. Michiru Matsushima, a tsundere with a dual personality, struggles with her identity and self-worth due to a childhood marked by neglect and manipulation. Sachi Komine, a stoic and disciplined maid, grapples with guilt and a distorted sense of duty stemming from a traumatic family incident. Yumiko Sakaki, a reclusive and sharp-tongued loner, harbors deep-seated resentment and fear due to her abusive upbringing. Makina Irisu, the youngest and most innocent-seeming, carries the weight of a fractured family and a life overshadowed by political intrigue.

As Yuuji interacts with each girl, their individual stories unfold through a series of arcs, revealing the depth of their struggles and the events that led them to Mihama Academy. Yuuji’s own past is gradually unveiled, exposing his involvement in a covert government program that trained him as a highly skilled operative. His experiences, marked by violence and loss, mirror the pain of the girls, creating a bond of mutual understanding and healing.

The narrative explores themes of trauma, redemption, and the search for identity, as the characters navigate their emotional scars and strive to rebuild their lives. The series balances moments of levity and camaraderie with darker, more introspective tones, reflecting the complexity of its characters and their journeys. Through its interconnected storylines, "Grisaia no Kajitsu" presents a multifaceted exploration of human resilience and the impact of shared experiences on personal growth.