Dr. Jack Hammond has best chances to become medical superintendent in the clinic. So he's completely absorbed in his work and has no understanding for his teenage son Chris' problems with school. By accident one of them drinks a brain-exchanging serum, and it switches their identities. This leads of course to extraordinary complications in school and at work, but also to insight in the problems and feelings of each other.

Gib, a beer-guzzling slob, and Alison, an uptight Ivy-Leaguer, are an unlikely duo stuck together on a cross-country trip during Christmas break. At first they get on each other's nerves but, as time passes, they find their divergent natures complement each other. Now they need to realize what they've already found before it's too late.