Lowell is paranoid about his wife, Bunny, flirting with other men. When Brian offers to help by talking to Bunny, he gets more than he bargained for.

The crew is invited to the wedding of the air traffic controller.

Lowell and Bunny make their separation final by signing the divorce papers only to start sleeping together again. Meanwhile, Antonio consoles a woman who's cheating husband left his cellphone in Antonio's cab.

Lowell's ex-wife arrives on Nantucket for a friend's wedding. Brian faces the prospect of meeting Alex's parents. Joe deals with the loss of a tree and Fay becomes overbearing as Helen organizes a holiday party for children.