Anzu Hanashiro transfers from Tokyo to a rural town, initially projecting a cool, aloof demeanor that distances classmates. This detachment results from family conflict, specifically disownment by parents opposed to her ambition of becoming a manga artist, following her grandfather's financially burdensome career path. Her strong will manifests physically when she strikes back against bullying over her manga with a decisive punch. Her first encounter with Kaoru Touno happens during rain at a train station. Revealing she has "no parents," she reluctantly accepts his umbrella, leading to an exchange of contact information and establishing a connection rooted in shared isolation. Discovering the existence of the rumored Urashima Tunnel, said to grant wishes at a cost, she proposes a partnership with Kaoru to investigate it, seeking the talent necessary for manga success. Their investigations uncover the tunnel's properties: time dilation where three seconds inside equal two hours outside, and its ability to return lost items. Inside, Anzu retrieves discarded childhood manga pages torn by her father. This discovery prompts her to confide in Kaoru about her grandfather's struggles as a failed artist, her family's rejection, and her deep-seated fear of inadequacy. Encouraged by Kaoru, she submits her work. Her relationship with Kaoru deepens through shared experiences like an aquarium visit and summer festival. She expresses a desire to remain with him, contrasting his wish to revive his deceased sister. When Kaoru enters the tunnel intending to stay, she receives his message revealing the tunnel's true nature—it cannot grant wishes, only restore lost things—and his plea for her to pursue manga so he might see her work if he escapes. She responds that her true wish was simply to be with him. Following Kaoru's disappearance into the tunnel, Anzu becomes a moderately successful manga artist. Eight years later, disillusioned and overworked, she returns to the train station of their first meeting, collapsing in tears while confessing she never forgot him. Upon receiving a sudden message from Kaoru, she rushes to the tunnel entrance. She witnesses his emergence thirteen years after his entry, and they reunite with a kiss.