Rin, Kazuma and I have been together since we were little. Today we are on a hot spring trip that Kazuma gave to Rin and Rin. Kazuma stamped the witness section of the marriage registration while laughing, saying that marriage between childhood friends is just a drama. That night, the three of us were drinking and reminiscing about old times, but the lounge was about to close, so I left first and headed to the hot spring. When I got out of the hot Rin, Rin was not in the room, even though she was supposed to be there. I got worried and called Kazuma, but...