Plot
In 2018, three years after his loss to "Pretty" Ricky Conlan, Adonis "Donnie" Creed, alongside his trainer Rocky Balboa who has beaten his cancer, has won six straight bouts, culminating in a victory over Danny "Stuntman" Wheeler to win the WBC World Heavyweight Championship, and reclaimed his 1967 Ford Mustang which he had lost to Wheeler in a bet. Now a worldwide star, Adonis proposes marriage to his girlfriend, Bianca Taylor, who accepts. Bianca suggests starting a new life together in Los Angeles, but Adonis is reluctant to leave Philadelphia and Rocky.
In Ukraine, Ivan Drago, the former Soviet boxer who killed Adonis' late father Apollo during a bout in 1985, has been living destitute since losing to Rocky that year, and seeks to regain glory. Assisted by promoter Buddy Marcelle, Ivan pits his son, Viktor, against Adonis. When Rocky, out of fear for Adonis possibly suffering the same fate as Apollo, refuses to support Adonis' acceptance of Viktor's challenge, Adonis leaves for Los Angeles.
Adonis and Bianca settle in a luxurious apartment in Los Angeles close to Adonis' adoptive mother and Apollo's widow, Mary Anne. As they adjust to their new life and prepare for the upcoming match, Bianca learns that she is pregnant. Adonis recruits Tony "Little Duke" Evers, son of his father's trainer and later Rocky's trainer Tony "Duke" Evers, to start training him. However, Adonis becomes overwhelmed by his life's recent developments, rushes into the match in Barclays Center unprepared, and is badly injured by Viktor. Viktor, however, is disqualified for hitting Adonis while he is down, allowing Adonis to retain the World Heavyweight Championship. Nevertheless, Viktor becomes extremely popular in Russia and wins a series of fights with top billing.
His body and ego shattered, Adonis becomes increasingly disconnected from Bianca. Mary Anne reaches out to Rocky, who reconciles with Adonis and agrees to train him for a rematch against Viktor, who is suffering torturous physical tests at Ivan's hands. Bianca gives birth to a daughter, Amara, and Rocky is named her godfather; Amara is born deaf, inheriting her lack of hearing from her mother's progressive hearing disorder.
While Viktor taunts Adonis publicly, he faces constant pressure from his father behind the scenes, who enjoys the attention of the media and various Russian delegates. At a state dinner, he and Ivan encounter Ludmilla, his mother and Ivan's ex-wife, for the first time in several years after she abandoned them following Ivan's loss to Rocky. Enraged at the sight of her, Viktor storms out of the dinner and chastises Ivan for seeking approval from those who cast them out. Meanwhile, Rocky and Little Duke retrain Adonis in a decrepit location in the California desert, focusing on fighting from within and training Adonis' body to absorb the heavy impact he will receive from Viktor in the ring.
In Moscow, the rematch is more balanced as a more controlled and focused Adonis exchanges equal blows with Viktor. Viktor is used to winning by knockout as his bouts have never lasted past four rounds; Adonis uses this to his advantage and willingly endures a heavy beating from Viktor, even after his ribs are broken. In the tenth round, Adonis unleashes sequences of effective blows on a now exhausted Viktor, leading to him knocking Viktor down twice. Ludmilla departs after the second knockdown, deeply upsetting Viktor, who loses the will to fight, and Ivan sees the truth of his son's earlier words. An exhausted Viktor is cornered and receives multiple strikes without defending himself, but is unwilling to go down. Finally realizing that his son's safety means more to him than revenge or acceptance from Russia's elite, Ivan throws in the towel, forfeiting the fight to protect his son. He assures the distraught Viktor it is okay that he lost, and embraces him. As Bianca enters the ring to celebrate with Adonis, Little Duke, and Creed's other trainers, Rocky excuses himself and takes a seat to watch them from outside the ring.
Following the match, Viktor and Ivan later train together back in Ukraine. Rocky travels to Vancouver to make peace with his own estranged son, Robert Jr., and meets his grandson Logan for the first time. Adonis and Bianca visit Apollo's grave, where Adonis makes peace with his deceased father and the burden of carrying on his legacy, as he and Bianca introduce Amara, who now has a new set of hearing aids.