One day, I decided to go on a hot spring trip with my girlfriend's best friend, and I met her for the first time, Yuka, who was my ideal type and fell in love with her at first sight. However, when she learns that Yuka is engaged to her boyfriend, she is heartbroken. That night, when Yuka heads off to the hot springs alone, I can't think of anything, so I follow her even though I know it's no good...