When Yuta was young, he met a girl named Rika Orimoto. They became inseparable, and on his 10th birthday, Rika gave him a ring. The two children promised they would grow up and get married. As the years passed, they eventually became a couple.

But in high school, tragedy struck. Rika was hit by a truck right in front of Yuta’s eyes. Overwhelmed by grief and an unconscious refusal to let her go, he isolated himself, but the pain never faded. It haunted him until he could no longer bear it.

One night, Yuta went to a lake, ready to drown himself. Then a voice echoed in his head, familiar yet strangely twisted, begging him not to do it. Confused, he searched everywhere, but no one was there. So he jumped.As he sank, time seemed to slow, and his life flashed before his eyes: the day he met Rika, the promise they made, and how much she had changed him. He closed his eyes and whispered a prayer.

“If I can’t be with you in this world, I wish we could be together in another one.”

The same voice answered.

“Then let’s live together in another world...”

Something pulled him toward the bottom, yet the lake seemed to have no bottom at all. Then the water began to recede, as if whatever held him wasn’t dragging him down but pushing him out.

When he opened his eyes, the world was different. The voice returned.

“Let’s live together in this world.”

With no other choice, Yuta decided to live on and uncover what had really happened, and who the voice belonged to.