After moving in with Rachel, Adam learns that she is still married; Karen agrees to have another child with David, but then finds out he's made a bad investment; Pete and Jenny have difficulties with their newborn baby.

David seeks sexual advice from Adam, saying that Karen just doesn't arouse him anymore; Pete seeks to resume intimacy with Jenny now that their baby has been born.

A meeting with a famous and handsome author, who wants her to edit his new novel, tempts Karen with thoughts of adultery; Adam is inspired to resurrect an old novel he was writing; and Pete's controlling parents make a visit.

Tired of Adam's preoccupation with a glamorous female neighbor, Rachel decides to baby-sit for Pete and Jenny, who need to get out so that they have something to talk about besides the baby. Meanwhile, David and Karen decide to see a marriage counselor.

David and Karen invite the other couples to a black tie charity dinner where David spends the evening networking, but Jenny gets drunk and starts a fistfight with his female boss. Meanwhile, Rachel reveals a secret to Karen.

Adam and Rachel wage a territorial battle over whose place to move into; David and Karen hire a nanny and differ over the issue of having another baby; as Pete and Jenny anxiously await the birth of their first child, Pete's meticulous planning comes to pieces when he mislays his mobile phone.