A la suite d'un accident de laboratoire, une immense créature génétiquement modifiée est lâchée dans la ville et terrorise la population. Toutes les forces doivent être rassemblées pour arrêter cet être qui possède des capacités physiques qui dépassent l'imagination.

Before the action-oriented buddy movie formula settled into place in the 1980s and 1990s with the Lethal Weapon films, Walter Hill's 48 HRS. presented a much more irreverent and politically incorrect version of the genre. Eddie Murphy made an auspicious film debut alongside veteran Nick Nolte's consummate performance as a worn cop. Murphy plays a convict on a two-day furlough from prison to help capture his former partner (James Remar). The intense animosity between his character and Nolte's impatient detective is rude and violent--albeit in a comic way--and the film's racist and sexist banter is so ubiquitous that some viewers might be turned off. (This early, raw Murphy is not the Murphy of The Nutty Professor.) Then again, sometimes deliberate overkill is funny in itself, which is certainly closer to Hill's intention. There are a couple of scenes for the ages in this film, especially Murphy's single-handed shutdown of the action in a redneck bar.