Lance Sterling, portrayed by Will Smith, is a brash secret agent working for H.T.U.V. (Honor, Trust, Unity and Valor). His latest mission leads him to Japan, where he aims to retrieve a dangerous attack drone from the notorious arms dealer Katsu Kimura, played by Masi Oka. However, things take a dramatic turn when the cybernetically enhanced terrorist, Killian, who is played by Ben Mendelsohn, arrives to thwart Sterling's plans. Killian, with his powerful bionic arm capable of controlling an army of armed drones, poses a severe threat to the world. Ignoring the orders of H.T.U.V. director Joy Jenkins, portrayed by Reba McEntire, Sterling tackles Kimura's gang, overpowers them, and manages to escape with the critical briefcase.
Upon returning to H.T.U.V. headquarters, Sterling confronts Walter Beckett, a socially awkward yet brilliant MIT graduate, played by Tom Holland. Walter is the mastermind behind the new nonlethal weaponry Sterling had been equipped with. As Walter attempts to persuade Sterling that there are better ways to approach their missions, mentioning a method to make agents "disappear," Sterling dismisses him before Walter can introduce his most innovative invention: “biodynamic concealment.” The tension escalates when Sterling discovers the briefcase is empty and is framed by Marcy Kappel, portrayed by Rashida Jones, who shows footage that suggests he's betrayed the agency.
Now on the run, Sterling teams up with Walter to find a way to clear his name while evading capture from H.T.U.V. Meanwhile, Killian brews trouble by infiltrating the agency's weapons facility. During an unexpected turn of events at Walter's residence, Sterling accidentally consumes a formula that transforms him into a pigeon. As Marcy and other agents pursue them, they escape using Sterling's spy car and head to Playa Del Carmen, Mexico, to trace Kimura's whereabouts, learning of Killian's next move in Venice, Italy.
In Venice, Walter faces the H.T.U.V. agents who are oblivious to Sterling's predicament. When Marcy confronts Walter about his mother, Wendy, a fallen officer, he stands by his decision to protect Sterling despite her pressures. A surprising drone distraction allows them to slip away, leading them to a drone containing the H.T.U.V. agent database. Yet, their victory is short-lived as Killian appears, seizing the database, intensifying the stakes.
Pursuing Killian involves teamwork and clever tactics as Walter plants a tracking device and subsequently perfects the antidote, restoring Sterling to his human form just before a showdown at the weapons facility. However, the battle escalates when Killian threatens to unleash his army of drones. Walter risks everything, trapping Killian and disabling his arm, but not without peril. In a dramatic scene, Sterling, having regained his pigeon form, learns to fly for the first time and saves Walter, ensuring the villain's capture.
Despite their heroics, both Sterling and Walter face termination for their actions, only to be reinstated when the agency realizes the value of their unorthodox methods of problem-solving. The story concludes with Sterling acknowledging his unique bond with Walter, as they embark on new missions that combine courage and innovation to combat evil.
