After a small lake town is attacked by mutated, blood-sucking lampreys, an animal control specialist takes on the responsibility to bring the situation under control and protect his family.

Dave is a married man with two kids and a loving wife, and Mitch is a single man who is at the prime of his sexual life. One fateful night while Mitch and Dave are peeing in a fountain when lightning strikes, they switch bodies.

When his buddies skip the annual guys' trip to stay home with their families, Boog the bear heads out on his own and hooks up with a traveling circus.

A man is so eager to become a dad that he'll believe anything, including the notion that a baby-faced thief on the lam is really an abandoned toddler.