Steve Martin is Harris Telemacher, a wacky television weatherman, who thinks his life is perfect, except for an erratic relationship with a style-conscious girlfriend (Marilu Henner). Then, one bright and smoggy L.A. day, an electronic freeway sign changes his life, when its advice leads him into a frivolous romance with a young and beautiful blonde (Sarah Jessica Parker) and, ultimately, to true love with the woman of his dreams (Victoria Tennant).