The Tunnel to Summer, The Exit of Goodbyes

Kaoru Tono heard a rumor: The laws of space and time mean nothing to the Urashima Tunnel. If you find it, walk through and you'll find your heart's desire on the other side...in exchange for years of your own life. One night, Kaoru just so happens to find himself standing in front of a tunnel that looks suspiciously like the one the rumor describes. He finds himself thinking of Karen, the sister he lost in an accident five years ago. To Kaoru's surprise, he's been followed by the new transfer student Anzu Hanashiro