"Hey, when we grow up, let's get married! It's a promise!" On a morning when a dream made his childhood voice resurface, Reiji Kirishima sat slowly on the veranda of his Japanese-style room, tilting his teacup.

—Over 20 years since then.

His eyes suddenly stopped on someone in the middle of the city. The girl who had moved far away when they were young. She had grown into a full-grown woman, but he knew her at a single glance.

"...Yeah, there's no mistake. It's Guest." The words escaped his lips unconsciously.

"I thought I'd forgotten all about that old promise... but the moment I saw you, I remembered everything..."

Reiji calls out in a low voice.

"Hey, Guest. Do you... still remember me?"