Natsu e no Tunnel, Sayonara no Deguchi

Following a period of familial upheaval, Kaoru Touno seeks solace and unexpectedly discovers a hidden passage – the Urashima Tunnel. This enigmatic conduit exists as a rumored gateway to fulfilling desires, at a cost to one's time. A brief journey through the tunnel grants him the improbable return of his deceased pet, sparking a desperate hope for reconciliation within his fractured family.

His renewed hope is complicated by Anzu Hanashiro, a new classmate who reveals her own knowledge of the Tunnel and proposes a collaborative endeavor. The pair find themselves drawn into a shared pursuit, each harboring personal wishes they believe the Tunnel can grant. As their connection deepens, they must confront the implications of altering fate and the true value of the sacrifices demanded by the passage's power. The series explores themes of loss, regret, and the complexities of pursuing impossible remedies.