The Tunnel to Summer, the Exit of Goodbyes – Ultramarine Vol.2 English Version Manga

Kaoru and Anzu have joined forces to study the mysterious Urashima Tunnel, which is rumored to give you your heart’s desire—in exchange for years of your life. As they explore, connected by a length of string, the two students discover other connections in their everyday lives, including seeing a new side of Kawasaki, the school’s arrogant queen bee.