Dos extraños se despiertan en la misma cama y descubren que se han casado tras una noche de desenfreno en Las Vegas, y que uno de ellos ha ganado un gran premio en un casino. Los recién casados comienzan a hacer planes cada vez más complicados para acabar el uno con el otro y quedarse con el dinero, pero solo conseguirán acabar enamorándose entre las mutuas puñaladas por la espalda.

Joy McNally is driven career woman who is engaged but when her fiancé grows tired of her uptight attitude; he breaks up with her. Jack Fuller is a guy who likes to goof off, which makes his boss who also happens to be his father, fire him. Feeling down they both go to Las Vegas to forget about what happened to them. When they get there, a computer error puts them in the same room. And after getting drunk, they wake up to discover they got married, which they both want to get out of. But when they win 3 million dollars, the ownership of which comes into question. When they decide to take it to court, the judge decides that they should remain married for 6 months and attend counseling sessions. So Joy moves in with Jack. And they both learn that if one of them asks to get out of the marriage, the other will get the money. So they each try to drive the other to want to get out of the marriage.