I'm a university student who works part-time at a convenience store. I went home today after work and was resting when the intercom suddenly rang. I'd just started living alone and hadn't had anyone come to visit, so I opened the door timidly and found my junior from work, Karin, standing there. Apparently, I'd left my wallet at work and she'd returned it to me. She kept pushing me to let her in because she'd brought me a gift, so I gave in and let her in...