When Samantha LeBon hatches a scheme to spend a romantic Christmas with her new employee — the unsuspecting, blithesome James — his wife, their kids and their two dogs, Rocks and Daphne, must rescue him before he makes a terrible mistake.

The luxurious villa of Mark and Jessie Bannister, a yuppie couple, is overrun by loads of uninvited guests who turn the house up side down.