Bea (Rose Byrne) and Thomas (Domhnall Gleeson) get married, and even though Peter once disliked Thomas, he finally accepts him and is even appointed the ring bearer.
However, Peter still feels Thomas is suspicious of him and thinks Peter is up to no good, even yelling at him when someone else steals a tomato.
When Peter hears the couple discussing their future children and Thomas says the children will be better behaved than the rabbits, Peter feels that maybe Bea and Thomas would be better off without them. He and his rabbit family take a train to the city, where they discover wonders such as a Farmer's Market. Along with a pig, a badger, a hedgehog, a deer and several other animals, they try to steal some of the beautiful fruit and vegetables on display, but when some of them are caught, they're locked into cages.
Desperate to free them, Peter returns home to ask for help and is surprised when Thomas goes to great lengths to get the animals back.