Defending the bullied son and the ending

Marina Shiraishi is a single mother raising her children for 17 years now. Her son is grown up but not as wise as others, so he is often bullied by a group of special students, but she does not know this. One day he took his friend home but something was wrong because his friend grabbed her son's collar while she was cooking. Marina went to school to pick up her child and saw her child being bullied. She was going to talk to the teacher to handle this incident, but the next day, a group of special students came to Marina's house to gang rape her. What a pitiful mother!