On a critical assignment in Budapest, IMF agent Trevor Hanaway meets his demise at the hands of an assassin known as Moreau. Following his death, Hanaway's team leader, Jane Carter, along with newly promoted operative Benji Dunn, orchestrates a daring rescue of Ethan Hunt ([Tom Cruise]). He emerges from a Moscow prison, motivated by his determination to save his informant, Bogdan ([Miraj Grbic]), from a grim fate of torture and execution.
Once successful in their escape, Jane reveals to Ethan that Hanaway was killed while attempting to intercept a standard courier drop containing highly sensitive Russian nuclear launch codes now in the possession of an assassin. The urgency escalates when Ethan learns that the notorious figure, Cobalt, has been threatening a catastrophic nuclear detonation. With Cobalt's alarming intentions, the mission becomes a race against time. Cobalt, a nuclear strategist for Russian intelligence, must be tracked down as he will stop at nothing to obliterate any traces of his identity.
Tasked with locating Cobalt, Ethan leads Jane and Benji to infiltrate the Kremlin's secret archives in search of critical files. However, they soon discover that Cobalt is already making moves to secure his position, leaving Ethan with a mere five hours to succeed. In a tense moment, Ethan navigates through the Kremlin’s security systems, only to be met with an empty records room. Suddenly, a broadcast over the IMF frequency alerts the Russians to their presence, compelling Ethan to give the command to abort. In the chaos of their escape, a bomb detonates, devastating the Kremlin and leaving Ethan caught in the explosion, only to awaken in a Russian hospital where he is accused by Agent Sidorov of orchestrating the attack, landing him in an even tighter spot.
Racing to freedom, Ethan's luck turns when the IMF manages to extract him, as the fallout from the attack prompts the US president to initiate "Ghost Protocol," a covert operation disentangling the entire IMF from government ties. Now marked as scapegoats for the Kremlin's destruction, Ethan and his team must evade capture while seeking out Cobalt. The grim situation worsens when they lose their secretary ([Tom Wilkinson]), killed during a skirmish with Russian forces, leaving Ethan and intelligence analyst William Brandt to plot their escape.
Through deduction, Brandt identifies Cobalt as Kurt Hendricks, a radical nuclear strategist who believes in the survival of the fittest and aims to spark a nuclear war for a new evolution of humanity. Having bombed the Kremlin and acquired a launch-control device, Hendricks is on the hunt for the launch codes previously in Moreau's possession, with intentions to target America.
In one of their covert IMF sites, the team devises a ploy to deceive Hendricks’s right-hand man, Wistrom, during an exchange set to take place at the iconic Burj Khalifa in Dubai. The plan involves a high-risk maneuver where Ethan must climb the exterior of the skyscraper to hack into the server room. They manage to create the illusion of an exchange between Moreau and Wistrom while navigating a web of deception. Yet, as chaos ensues, Hunt realizes that Wistrom is actually Hendricks in disguise. In a chase filled with unexpected turns, Moreau threatens to end Dunn’s life, leading Carter to act decisively by eliminating her adversary. Tensions rise as accusations fly between Carter and Brandt regarding mission integrity and hidden truths.
Amidst the growing personal stakes, Ethan seeks clarity from Bogdan about Hendricks's next move. Confronted with haunting memories of his late wife, Julia ([Michelle Monaghan]), Brandt reveals his connection to Ethan’s past, further complicating their dynamics. The implications of their mission deepen when they learn Hendricks is headed to Mumbai, where he plans to leverage a defunct Soviet satellite to transmit missile commands.
With time running out and Hendricks anticipating their every move, the stakes escalate rapidly. When Hendricks triggers a missile aimed at San Francisco, claiming it to be a direct response to perceived threats, the only hope lies in seizing control of the launch device he possesses. A heated confrontation ensues in an automated parking facility as Ethan battles Hendricks. In a moment of desperation, Hendricks jumps to his death, device in hand, ensuring the launch remains intact. Meanwhile, Dunn takes decisive action against Wistrom, allowing Brandt to restore power to the broadcast station, which ultimately enables Ethan to thwart the missile's launch.
As the dust settles, Sidorov realizes the truth behind the Kremlin incident, validating the innocence of the IMF. In the aftermath, Ethan gathers his team, offering new assignments while revealing a crucial secret—Julia's death had been staged to protect her. This revelation lifts the weight of guilt from Brandt's shoulders, prompting him to embrace his new mission. As they prepare for their next adventure, Ethan watches Julia from a distance, sharing a bittersweet smile that signifies hope amid chaos.
