Mark and Jenn struggle to make their relationship work after he moves in with her in Milwaukee. Doug coaches Jake's Little League team. Chloe's irresponsibility wears Susan down. Carter decides to apply for both the ER sub-internship and the surgical sub-internship. Carol and Tag discuss their vows and other wedding details; he becomes upset when Carol invites Diane Leeds, knowing that she'll bring Doug. Benton exhibits a growing attraction to Jeanie. Susan discovers what happened to Div when she spies his picture in a cabbie's dating service photo book. The staff finds out that Carter comes from a wealthy family. Swift has to take over for Mark during a trauma.