Sins of the Father - S1.E3

The episode begins with a young boy screaming from inside his bedroom. The door is locked, and his mother can't get in. When the police arrive, she tells them that her husband is in the room beating her/his son up. The police broke down the door and took the husband away. David tells his wife that it wasn't him who beat up his son in the bedroom, but it was some un-foreseen force. And that Michael is still in danger.

The next morning Derek goes to visit David at his home, David has been bailed out of prison by his father. Derek heard about the arrest and wanted to see if it was true. David tells Derek that it wasn't him. David shows Derek a scar on his chest which he claimed he received at the hands of this unforeseen force who attacked Michael. It turns out though, that David was drunk last night. Derek asks David if Rachel will be ok to examine Michael. David agrees.