Franklin Carlton Ferrana, Jr. has reached a breaking point with his mother's endless parade of partners, an ongoing saga that began after his father walked out on them. Tragically, he finds himself burdened with his father's name. In a bold attempt for revenge against his latest stepfather's abuse, Frank takes drastic action, culminating in a shocking incident that leads to the police being summoned. Fast forward ten years, and we find Frank now residing in Los Angeles, where he stands in line at the county court waiting to collect his new ID. As he burns his old identification, we discover he has legally transformed his name to Nikki Sixx. Upon exiting the courthouse, he destroys his former identity, marking a definitive break from his past.
Meanwhile, at the Bass household, Tommy Lee is navigating his own life's challenges, marked by a disagreement with his sister regarding his unconventional fashion choices for an upcoming performance. After one of Tommy's shows, whispers about Nikki's burgeoning reputation reach his ears through their music circles. Feeling anxious yet determined, Tommy ventures to a local diner to enlist Nikki's participation in his band, and after a few rounds of Jack Daniels, Nikki agrees. They realize they need more talent to complete their lineup, including a bassist and a vocalist.
Tommy takes the initiative by placing a personal ad in the LA Weekly, which ultimately attracts Mick Mars, whose stage name echoes his true passion. However, Mick's journey is perilous due to a rare degenerative bone illness that complicates their path. As they solidify their band, the final piece falls into place when Tommy remembers Vince Neil, a high school acquaintance who might just fit the bill. Seeking him out at a local party where Vince is performing, Tommy rekindles their friendship and convinces Vince to join them once his current commitment evaporates.
With the lineup complete, the group desperately brainstorms names for their nascent band over a few drinks, but to no avail—until Mick steps forward and suggests a name he'd long held onto. And thus, Mötley Crüe is born. Their debut performance is anything but perfect; Tommy faces a catastrophe when his drum kit collapses mid-show, leading to unwanted heckling from the audience. Nevertheless, they manage to reclaim the night, turning the debacle into a triumphant moment.
As they embark on their newfound journey, fans flock to their performances along the iconic Sunset Strip, revering them as they unleash a lifestyle filled with excess and wild parties alongside luminaries like David Lee Roth and Eddie Van Halen. Their notoriety amplifies following a stellar gig at the Forum, which leads to a coveted tour with rock legend Ozzy Osbourne. The wild reputation of the Crüe continues to grow, largely fueled by their reckless partying and hotel room destruction. Despite warnings from Ozzy about the potential repercussions of their lifestyle, chaos looms on the horizon.
As they approach their third album's tour, tensions begin to rise. Vince grapples with the band's new sounds and faces pressure when venues steer them towards a path they aren't comfortable with. Meanwhile, Tommy's engagement to Roxy faces its own tribulations, leading to a heated incident, while Nikki feels disconnected from his mother during a visit that stirs mixed emotions.
By 1984, Vince has acquired a stunning mansion in Redondo Beach, where he holds a housewarming party that introduces Tommy to Heather Locklear, who would eventually become his wife. However, tragedy strikes when Vince is involved in a horrific car accident that results in the death of Nick Dingley, the drummer for their opening act, Hanoi Rocks. This incident leaves Vince facing jail time for vehicular manslaughter, deepening the cracks within the band.
Nikki candidly reflects on the grueling realities of touring life. The relentless cycle of late-night parties, strip clubs, and performances takes its toll on their psyche. Amidst Tommy's wedding chaos, Nikki finds himself spiraling due to his intense heroin addiction, almost sabotaging his friend’s special day. Fortunately, he is revived by a paramedic who happens to be a devoted Crüe fan.
Determined to reclaim his life, Nikki seeks help from his bandmates, and together they venture into rehabilitation. Transitioning from wild partying to sober living, they release "Dr. Feelgood," a personal and hard-fought reflection of their struggles, ultimately achieving number one status. However, maintaining their sobriety strains relationships between band members, leading to Vince's departure to care for his sick daughter Skyler, who faces a challenging battle.
As the group grapples with Vince's absence and a tumultuous new era following the introduction of John Corabi, the band’s future appears bleak. Yet, following an emotional reunion at a bar, they rally around Vince, who mourns his loss and honors his daughter's memory by returning to the stage. Their bond is rekindled, allowing the Crüe to embark on another remarkable and successful journey. Ultimately, the film concludes with footage of their final performance on December 31, 2015, capturing the enduring legacy of the band as they reclaim their glory one last time.
