Tony (Connor Esterson) and Patty (Everly Carganilla) excel in online gaming, spending most of their free time indulging in this thrilling pastime. Recognizing this obsession, their parents, Terrence Tango (Zachary Levi) and Nora Torrez (Gina Rodriguez), set strict boundaries. Being spies themselves, they are particularly wary as their computers house the highly classified Armageddon code. They fear that if their children’s devices are compromised, their top-secret information might be stolen.
Their boss, Devlin (D.J. Cotrona), alerts them to a looming threat: unknown foes are attempting to breach OSS servers to administer the Armageddon code. Despite allowed gaming hours, Tony bends the rules, sneaking late-night gaming sessions with Patty, who values honesty and adherence to their parents' guidelines. Tony, however, believes that bending the truth is acceptable, asserting, >“One should have their way by hook or by crook.” He eventually enters a tournament for a game called Hyscore, winning access to it—though he cheats to do so.
One fateful night, as they explore the newly acquired game, Tony circumvents his parents' digital safeguards to log in using a password he discovered. But just as they begin, the screen goes haywire, and their computer crashes, prompting a swift retreat to their bedroom to avoid getting caught. The creator of Hyscore, Rey 'The King' Kingston (Billy Magnussen), had deceitfully infiltrated their system in an effort to steal the Armageddon code, which grants entry to any device in the world—a tool for domination.
Meanwhile, a fierce debate arises between Terrence and Nora on whether to delete the Armageddon code to safeguard it from evil. Terrence argues against deletion, believing they'll need the code to combat various threats, but Nora, in a moment of clarity, decides to erase it. Before she can execute her decision, however, Rey hacks their system and successfully steals the Armageddon code, resulting in chaos worldwide as Hyscore inadvertently installs itself on numerous devices.
After returning to consciousness, Terrence is met with a tumultuous situation as the Hyscore character launches an assault on their home. They expedite sending the children to a safe house but fall victim to capture by Rey Kingston. Just before they are separated, Nora gifts Patty a locket containing half of the Armageddon code.
Unbeknownst to Rey, a divided code has thwarted his ambitions, as he only acquires a portion of its power. Realizing the other half is hidden within Patty's locket, he dispatches his agents to find the children and bring them to his lair. Meanwhile, Tony and Patty, demonstrating resourcefulness and courage, uncover various gadgets in the hideout and begin training themselves to become effective spies.
The OSS agents soon locate the hideout and bring the children to Devlin. Tony and Patty reveal Rey as their primary suspect prompting Rey's goons to launch an attack on OSS HQ, ultimately capturing the second half of the Armageddon code. With bravado, the children pursue the criminals using OSS technology and track down their parents' location via Nora's tracker.
As they gather, Terrence shares a pivotal revelation about the Armageddon code's origins, disclosing that it was constructed based on a weapon blueprint from a past mission involving the villain Vargos. Tragically, Rey is unveiled as Vargos' son, seeking vengeance for what he believes was an injustice against his father. Patty articulates her belief that their parents could have handled the situation without bloodshed—a notion that surprises Terrence and Nora.
Arriving at Rey's lair, the siblings manage to rescue their parents but find themselves in a precarious situation, as Rey is already activating the virus intended to unleash chaos across the globe. As the countdown begins, Tony realizes his critical mistake—he unwittingly armed Rey's system. However, Patty devises a daring plan; if they could enter the game realm, they could confront Rey directly and thwart his plans.
With determination, Terrence, Nora, and their children step into the virtual world of Hyscore, facing formidable adversaries from the game universe. In a test of skill and moral integrity, Patty urges her family to uphold fairness, even against treachery. As the conflict unfolds, it seems as if Rey might best Tony. Yet through an act of honesty, Tony earns an elusive opportunity—a "fair play" extra life—to ultimately triumph over the villain and successfully stop Rey.
Impressed by the children's show of compassion, Patty pleads with the OSS not to imprison Rey but to instead allow him a chance at redemption within the virtual world. Touched by their kindness, Rey realizes that true change can happen without harsh methods. The next day, the kids receive an invitation from Devlin to join the OSS as official spies, with new principles promising to eschew unfair practices. The story concludes on a hopeful note for the spy family, hinting at further adventures to come as they prepare to tackle new challenges and protect the world.
