In 1973, Frank Carlton Feranna Jr. walks away from his drunk mother Deana after years of abusive stepfathers and moves from Seattle to Los Angeles in 1978. After a failed attempt to connect with his biological father, Frank legally changes his name to “Nikki Sixx” in 1980. A year later, after a falling out with members of London at the Whisky a Go Go, Nikki befriends drummer Tommy Lee and reveals to him that he is forming a new band. Joining the band is guitarist Mick Mars, who suffers from ankylosing spondylitis. The trio then recruit lead vocalist Vince Neil from the cover band Rock Candy, and after some brainstorming, the quartet name themselves Mötley Crüe.
Despite being involved in a brawl with some crowd members, Mötley Crüe’s first gig at the Starwood becomes well-received, and they progressively sell out all over L.A.’s night clubs until rookie producer Tom Zutaut of Elektra Records approaches them with a five-album deal and they sign Doc McGhee as their manager. During their first national tour, the band is given advice by Ozzy Osbourne to know the limits of their partying before he snorts some ants and licks his and Nikki’s urine on the pool floor. Before long, the band’s albums go platinum and they each spend millions of dollars as fast as they earn them. Vince marries mud wrestler Sharise Ruddell, while Tommy announces his engagement to a woman named Roxie, but after his mother calls her a groupie, they get into a heated argument with Tommy punching Roxie in the face.
On December 8, 1984, during a party at Vince’s home in Redondo Beach, California, Tommy meets Heather Locklear. Vince and Hanoi Rocks drummer Razzle drive out to buy more drinks and get into a car accident that kills Razzle and has Vince sentenced to 30 days in jail for vehicular manslaughter, which is subsequently reduced to 19 days. Nikki becomes addicted to heroin and starts to display destructive behavior towards his bandmates. He fires McGhee for bringing Deana to visit him. On December 23, 1987, shortly after Tommy and Heather’s wedding, Nikki overdoses on heroin and is initially declared dead, but a paramedic who is a big fan of the band brings him back to life with two shots of adrenaline. Following this, Nikki has the band go to rehab. A sober Mötley Crüe rebounds in 1989 with Dr. Feelgood, which becomes their first number one album on the Billboard 200, followed by a lengthy world tour. The months of touring and staying sober take their toll on Vince and Tommy, who resort to drinking again after being away from their families for too long.
Following the tour, Vince discovers that Sharise and their daughter Skylar have left him, causing him to miss several rehearsals and eventually part ways with the band in 1992. The band then hires John Corabi as his replacement. In 1995, Skylar dies of stomach cancer at the age of four. Heather divorces Tommy after he is caught having an affair with a porn star. Seeing the backlash by fans over Vince’s departure from the band, Nikki negotiates with Zutaut to give them back the rights to their songs in exchange for their release from Elektra Records. After visiting his father’s grave, Nikki regroups with Tommy and Mick before they reconcile with Vince. Mötley Crüe would perform together for another 20 years, playing their final show on New Year’s Eve 2015.