Through a series of misunderstandings, Alvin, Simon and Theodore come to believe that Dave is going to propose to his new girlfriend in New York City - and dump them. They have three days to get to him and stop the proposal.
When minor-league hockey player Derek Thompson -- who has a penchant for knocking out his opponents' teeth every time he plays -- disillusions a fan, he is sentenced to a stint for one week as a bona fide, tutu-clad, real-life tooth fairy. Soon, Derek is inspired to rekindle his youthful dreams.
Loving but irresponsible dad Daniel Hillard, estranged from his exasperated spouse, is crushed by a court order allowing only weekly visits with his kids. When Daniel learns his ex needs a housekeeper, he gets the job -- disguised as a British nanny. Soon he becomes not only his children's best pal but the kind of parent he should have been from the start.
