In Fountain Grove, California, high school student Jeff Grant decides to enter the Air Force Academy upon graduation. At the Russian embassy in Mexico City, Mexico, officials order secret agent Konstantin Karpov to San Diego, California, to capture a rogue agent known as “Scuba.” He has already killed an important Russian agent working at the Internal Revenue Service (IRS), and will continue to kill KGB operatives until the agency pays him. At the Federal Bureau of Investigation (FBI) San Diego office, agent Roy Parmenter does a background check on Jeff Grant to vet his Air Force application. The computer reveals that Jeff’s parents, Richard and Elizabeth Grant, died in 1891 but opened a plant nursery in 1968. The contradictory information causes Roy to investigate further, and he personally interviews the boy, claiming it is for his admission to the academy. When Karpov arrives in Fountain Grove, Roy is notified that the agent has entered the country in search of Scuba. Although the FBI has chosen not to interfere with Karpov, Roy intends to avenge his partner, who was killed by Scuba twenty years earlier. Meanwhile, Jeff’s driver’s license is suspended after he receives several speeding tickets, but Roy arranges to have it reinstated in order to further interrogate the youth. Roy drives Jeff home, and requests that the boy not discuss the nature of their meetings. The following day, Roy questions Verna McLaughlin, Jeff’s guidance counselor, who claims Jeff is close to his civic-minded parents. Later, Jeff’s mother, Elizabeth, cleans a fish caught by her husband, Richard, and finds a suspicious plastic cylinder hidden inside. Late that night, the couple opens the cylinder and finds a coded message, which reads, “Kirov opening.” The next day, a Russian sailor’s body washes up at Sea World theme park, and Jeff learns that Roy is residing a house across the street from the Grant home. Scuba surprises Karpov in his motel shower, threatening to kill two more Russian spies unless he receives payment. Following a friendly game of basketball, Roy reveals that Jeff’s parents are Russian sleeper agents, who took their names from headstones in a cemetery. When Roy offers more details about their past, Jeff refuses to comment and returns home. Aboard a sightseeing boat, Karpov sends an associate to inform Scuba that his money is stored in a locker at the wharf. At the end of the tour, the boat captain finds the associate dead. Later, Roy shows Jeff photographs of all the sleeper agents Scuba has recently killed. Although Jeff’s parents are in danger, Jeff refuses to spy on them, believing that Roy is more interested in Scuba than his parents’ welfare. Later, Karpov surprises Elizabeth and Richard Grant at a Kirov Ballet performance. Despite protests that they are no longer useful to the KGB, Karpov believes otherwise, and orders them to deliver a bundle of money to Scuba. At home, Jeff searches for evidence of his parents’ true identities, and discovers their Russian passports in the greenhouse. Richard and Elizabeth return home and debate whether or not to tell Jeff the truth. Jeff confronts his parents with the Russian passports, but as Richard reveals his son’s Russian name, Karpov telephones, ordering the agents into action. While Richard begs for more time, Jeff runs to Roy’s house for help, and discovers Karpov on the telephone with his parents. Holding Jeff hostage, Karpov orders the Grants to deliver the money to the G Street pier. Roy returns home to find a Russian cigarette in the bathroom soap dish, which Jeff left as a clue. Roy runs to the Grant house, informing Richard and Elizabeth that Scuba intends to kill them. Regardless, the couple keeps their appointment with Scuba, carrying the money in a picnic cooler. Roy follows after learning their destination from a recording of the phone call. At the pier, Scuba’s meeting with Richard and Elizabeth is interrupted as Jeff attempts to escape from Karpov’s car. Roy wounds Scuba, and a mother and child steal the cooler. Scuba regains his footing and climbs aboard a docked boat, where he fights Roy. Meanwhile, Karpov and Jeff head for the border, with Richard and Elizabeth in pursuit. They board a trolley, and Richard pleads with Karpov to kidnap him instead of his son. At the next stop, Roy boards while holding Scuba at gunpoint. As Roy aims the barrel at Scuba’s ear, Karpov points his gun at Jeff’s head. Roy orders Jeff to his feet and a tense exchange of hostages is made. At the border station, the group disembarks and crosses a bridge. A pedestrian jostles Scuba, who breaks free and tries to throw Jeff over the guardrail. Richard rescues his son, but when Scuba kicks him to the ground, both Roy and Karpov fire shots at the agent. Roy and Karpov deliver the unconscious Scuba to a pair of Russian agents, who escort him across the border. Through the fence, Karpov tells Jeff he will miss him and invites the youth to visit him in Russia. As Jeff reunites with his parents, Karpov reminds Roy to be vigilant, and to remember that Russians do not shoot their children.