In a sleepy country town, a traumatized boy and a transfer student from Tokyo stumble upon a time-bending tunnel that may grant them their every wish.

Kaoru Touno's family is falling apart. After the death of a sibling and his parents' divorce, he no longer feels any peace at home. Following a heated confrontation with his father, Kaoru runs out of his house and finds himself before a mysterious tunnel, which pulls him in. Bewildered by what he sees inside, he rushes to the exit, picking up a bird that looks identical to his deceased pet on his way out. Upon emerging outside, Kaoru realizes that, despite him spending just a few minutes inside the tunnel, an entire week has passed. The bizarre experience leads him to remember the rumors of "Urashima Tunnel"-a passage that grants wishes in exchange for one's lifespan. Given the resurrection of his pet bird, Kaoru cannot help but wonder if another visit can help fix his messed up life. However, when he returns to the entrance of the mysterious tunnel, Kaoru realizes that he has been followed by Anzu Hanashiro, a new transfer student in his class. She also knows about the rumors and asks him to help her with an experiment-it turns out that she, too, has a wish that only the tunnel can grant.—MAL Rewrite

There is a phenomenon called the Urashima Tunnel, which exists outside the boundaries that constrain our reality. Unbound by such restrictions, it can achieve the otherwise impossible, journey wherever a mind can conceive, and bring the one thing that they most desire. But the cost of using the tunnel is staggering: a portion of one's own existence. Yet... when Kaoru Tono discovers something matching the Tunnel's description, he can't help but think of the sister he lost five years ago. Can the tunnel really reunite them? And how is his school's beautiful new transfer student involved? The answers await down a path into mystery in THE TUNNEL TO SUMMER, THE EXIT OF GOODBYES.—Sentai Filmworks