[Sasahara Rin Lesbian Debut] Rin is happily living her days, about to marry her boyfriend. One day, she accidentally drops her smartphone while returning from work and frantically searches for it, but cannot find it. The next day, someone suddenly returns her phone. Grateful to the woman, Rin breathes a sigh of relief. However, there's something strange about the woman's demeanor and presence, leaving Rin with an uneasy feeling. How did this woman know where she lived? How did she know about her phone? Rin's anxiety gradually grows. Then, she discovers the woman is a lesbian. What seemed like a simple incident of losing her phone becomes the beginning of Rin being targeted and cornered into a lesbian relationship. Her heart and body are slowly shaken, leading her toward a new romantic development.