SUNSET asks the kind of question that seems to fascinate second-rate studio hacks and leaves everyone else slackjawed with ennui: what if Wyatt Earp and Tom Mix had teamed up to solve a murder in the late 1920s? In 1929, the aging Earp (James Garner) is hired as technical advisor for a biopic about his life, starring Mix (Bruce Willis). The movie cowboy takes the real-life gunslinger under his wing, and the two team up to investigate the murder of a prostitute. The result is a ponderous package of suspenseless mystery and humorless comedy. Garner's plausible as Wyatt Earp, while Willis cuts an impressive figure in a cowboy suit, but they're done in by the burdensome story.