I work part-time at a convenience store. One day, when I was trying to go home after work, I couldn't because of a heavy rain... Then, my cheerful, short, younger sister-like junior, Yuri-chan, who had the same shift as me, offered to let me stay at her house. After returning home soaking wet, Yuri-chan changed behind me... At that time, I got a glimpse of her huge breasts, which were beyond imagination from her clothes... What's more, Yuri-chan seduced me by sticking her breasts to my arm...