John and Jane Smith are an ordinary suburban couple with an ordinary, lifeless suburban marriage. But each is hiding something the other would kill to know: Mr. and Mrs. Smith are actually highly paid, incredibly efficient assassins--and they work for competing organizations. Mr. and Mrs. Smith both discover a new source of excitement in their marriage, when they're hired to assassinate each other--and that's when the real fun starts. The result is a total action spectacle, as Mr. and Mrs. Smith put their formidable skills to work and their marriage to the ultimate test.