Despite the disapproval from the rest of the family and his own hesitations, Eric takes in Mary's ex-boyfriend Robbie Palmer (Adam LaVorgna) to live with the Camden's for the night after learning that he's homeless. Matt also shows up unexpectedly after being kicked out of his apartment by John, who needs quality time with his girlfriend. Meanwhile, Mary calls home again and hears Robbie's voice on the other end and assumes he's dating Lucy now. Also, John proposes to his girlfriend Priscilla in front of Matt.

Although Robbie is just as nervous as everyone else, his presence in the house during Mary's weekend stay causes a great deal of concern among the Camden's. Matt and Lucy are especially suspicious after Lucy accidently finds a condom in a misplaced wallet. Imagine their surprise when they learn that the provocative prophylactic belongs to Simon--- who just so happens to be spending the evening with his new lady friend, Sasha.

Matt begins to go crazy over a psychological evaluation that he is required to take for his medical-school application. Matt also notices the strange demeanor of his psychologist, which leads to a surprising twist. Meanwhile, after Ruthie gets into trouble at school for missing homeroom classes daily, she tricks Robbie into coming to talk to her principal. Simon decides he no longer wants to be together with Sasha since they have nothing in common and that she is not that intelligent, but the plan backfires on Simon. Also, Mike wants to try to be in a relationship with Lucy again, but unfortunately she turns him down since they are both on the rebound from Jeremy and Elaine. Lastly, Eric must convince a terminally ill patient to embrace life no matter what the doctors tell him.

Lucy and Robbie argue over who should tell Mary about their emerging relationship. Meanwhile, Matt worries that a young woman in his study group might be a victim of physical abuse at the hands of her belligerent boyfriend. Eric's sister Julie shows up at the Camden house with her toddler Erica and annoys Annie as she tries to prepare a lesson for her class. Simon meets up with Sasha and they both try to catch up on their personal lives.