Meguraian no Kimi

Masakichi-kun a first year high schooler working as an errand boy for the bullies upperclassmen slams by accident into a girl member of a biker gang, though touching her breasts... She saves him from a falling steel frame from a construction yard and leaves without saying anything..

Later on she suddenly shows up at his school causing a ruckus, what will happen to Masakichi-kun?