5x16 - 7th Heaven

Robbie is ecstatic when his long-lost father (guest-star Alan Thicke) who is a dead-beat dad appears out of the blue. Although, Eric and Annie distrust the dead-beat dad's motives. He also convinces Robbie to move out with him; against Eric's wishes. Meanwhile, Ruthie turns to Mary for advice on how to get around their parents rules when wanting to buy a makeup kit that they said 'no' to. Also, a very convinced Annie worries when Lucy starts having a relationship with her friend's freewheeling ""unmotherlike"" mom. Also, Simon develops a bad attitude with his mother when not wanting to do his school work, but wants to hang out with his friends.