Yuge Daisuke is a tour guide studying astronomy in his free time and a playboy who only gets involved in relationships with no strings attached. He meets Fujishima Rui on Oahu in early summer and falls in love with her at first sight. The two begin a romance; however, as the result of an accident, she suffers from amnesia and her memory gets reset every night. Daisuke has to woo Rui every day as she keeps forgetting him.