Anxious with age and retirement, homicide detective Roger Murtaugh (Danny Glover) is partnered with young and suicidal narcotics officer Martin Riggs (Mel Gibson).

Murtaugh and Riggs soon discover that Hunsaker was involved in a heroin-smuggling scheme led by a retired general (Mitchell Ryan) and his lead enforcer (Gary Busey).

This sparks a series of attempts at their lives, forcing them to take a less dangerous case, protecting Leo Getz (Joe Pesci), a loud-mouthed whistleblower with whom they gradually bond and befriend.

With assistance from Leo, they learn that the subject of the investigation is a rogue cop (Stuart Wilson) who is stealing impounded weapons and selling them on the black market.

[4][5] In June 2024, Gibson confirmed in an interview with the Inspire Me podcast that he would direct the fifth installment of the Lethal Weapon franchise and that the film would stay true to Donner's vision and influence.

[8] In September 2024, Gibson attended FanX Comic Convention in Salt Lake City, where he talked about the franchise, while voicing his frustration as to why Hollywood producers aren't giving him approval to work on the film.

[9] A television adaptation of the film series was developed by Matthew Miller as co-executive producer, along with Dan Lin and Jennifer Gwartz for Fox.