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 belligrent boyfriend. Elsewhere, 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. Lastly, Simon meets up with an old girlfriend, Sasha and they both try to catch up on their personal lives.