Charlotte is sent sprawling by a hit and run driver and fights to save her unborn child. Things with Mac are coming to a head for Cate. She suspects that he's on the verge of a decision that will send him back into arms of Gill - breaking her heart. Jessica's high-spirited but difficult bipolar patient refuses to medicate himself, but when he lets slip that he had a couple of car accidents earlier in the day her curiosity is piqued.