Zig Zag Don

Ichina is a 2nd year high school student. She lives with her mother Youko who she hates with a passion. After getting dumped by her boyfriend she ends up having a one-night stand with her best friend Sekitani who also recently broke up with his long-time girlfriend. Will they become more than friends? And who is the strange guy who's waiting at home with Youko when she gets back?