The reason for my overprotective mother (chapter one)

Nagisa had been locked up in his house since the age of six when he got abducted by someone. His mother started drinking after that and took her fears of Nagisa being addicted out on Nagisa. One night, a boy named Karma who goes to a middle school close to Nagisa's house walks by and hears screams from inside, what will Karma do? Will he leave it be or will he get involved?