Following the conclusion of Therapy Game, the sequel Therapy Game Restart picks up with the couple Minato Mito and Shizuma Ikushima as they navigate the transition from a fledgling romance to a more established, adult relationship.

The central conflict arises from a major life change for Shizuma, who has graduated from veterinary school and begins his new, demanding career as a resident veterinarian at a clinic. This new job leaves him with significantly less time to spend with Minato, creating a strain as they struggle to find moments for dates and intimacy. To resolve this growing distance, Shizuma proposes that the two of them move in together, a suggestion that forces both men to confront their personal anxieties about commitment and their future.

Minato Mito is a photographer who also works at the rabbit shop Trois Lapins, owned by his older brother, Itsuki. He carries deep-seated trauma from his childhood, following the collapse of his parents' relationship and their subsequent deaths, which makes it difficult for him to trust in the stability of relationships. He is proud of his identity as a gay man but struggles with fears of being seen as too clingy or of having his relationship fail. His partner, Shizuma Ikushima, is a newly minted veterinarian who identifies as bisexual. He is deeply committed to his career but must learn to balance his professional ambitions with his personal life. The pressures of his job are compounded by a colleague, Yamamoto, who develops an interest in him and by his demanding boss, Akira Onodera, a socially awkward but highly skilled veterinarian whose lack of communication creates additional professional hurdles for Shizuma.

The narrative of Restart follows the couple as they agree to move in together, with the plot exploring the delicate balance between their professional and romantic lives. Shizuma faces the trials of a new job, including proving himself to a difficult superior and managing his workload, often at the expense of his time with Minato. Simultaneously, Minato grapples with the loneliness of Shizuma's absence and the fear of placing too many demands on his partner, leading to moments of internal struggle where he holds back from being completely honest about his feelings. A key emotional beat involves Minato trying to nurture an unbloomed cherry blossom branch, which serves as a companion during his solitude. As they discuss cohabitation, Shizuma must learn not to be too insistent, while Minato must confront whether he believes he deserves a chance at a happy domestic life. The couple is supported by a cast of returning characters, including Minato's supportive brother Itsuki and his partner Shohei, Shizuma's brother, who offer advice and perspective from their own relationship.