But Billy's words of warning lead to disaster as Josh ends up in hospital.
Shona's worried about David when he insists on going for a walk and she speaks to Billy who offers to track him down.
As she goes through his receipt and finds a few for a particular cafe, Billy tracks him down and watch as he sits in his car and then follows a man coming out of some flats. As David stops outside a bar, he jumps in the passenger seat.
David explains to Billy that he has been watching Josh to make sure he doesn’t attack anyone again and that the guy he's been following has been spending a lot of time with Josh.