Tia and Tony Malone, young siblings from another planet who possess supernatural powers, travel on a spaceship with their Uncle Bene. After the aircraft lands at the Rose Bowl stadium in Pasadena, California, Bene sends the children off in a taxicab, wishing them a pleasant vacation in Los Angeles. Elsewhere, Dr. Victor Gannon and his spinster benefactor, Letha Wedge, arrive in downtown Los Angeles with Wedge’s nephew, Sickle. Using Sickle as a test subject, Gannon plants a chip behind his ear and manipulates a small control box to gain control over Sickle’s mind. Gannon orders Sickle to climb to the top of a building despite his crippling fear of heights. When Tia and Tony’s taxi runs out of gas, they wait in the car as the driver goes in search of fuel. Before Sickle slips and falls from the top of the building, Tony senses the tragedy about to happen and runs to his aid. Tony uses his ability to “energize,” or levitate, objects to stop Sickle in mid-air. Gannon observes Sickle’s body as it is slowly lowered to the ground by Tony. Recognizing Tony’s power, Gannon captures the boy, drugs him, and forces him into his car, just as Tia comes to look for her brother. Tia finds herself stranded in the midst of a gang war between some local teenagers called “The Goons,” and a group of younger boys who identify themselves as “The Earthquake Gang.” Tia teams up with the Earthquake boys and uses her powers to send garbage cans flying at the Goons. After the older gang is defeated, Tia explains to her new friends that she has just lost her brother, and they promise to help find him. They spot Mr. Yokomoto, whom they call “Yoyo,” a truant officer whose job is to ensure that the neighborhood kids attend school, and run in the opposite direction. At the gang’s hideout in an abandoned building, Tia attempts to contact Tony via telepathy, but Tony is unconscious and tied down to a table in Gannon’s laboratory. As Gannon and Wedge argue about money, Tony regains consciousness, but Gannon administers another shot, putting Tony back to sleep. Tia manages to visualize Tony’s surroundings and determines he is in a hospital of some sort. The next day, Gannon confirms his suspicion that Tony has the power to energize matter and hooks the boy up to his mind-control device. Once Gannon is out of sight, Wedge kidnaps Tony and takes him to a museum with plans to steal a large exhibit of gold, worth three million dollars. Tia has another vision of Tony’s whereabouts, and the Earthquake gang helps her deduce that Tony is at the museum. Utilizing the mind-control device, Wedge directs Tony to create a distraction at the museum. Chaos ensues as Tony causes a stagecoach to move around the room and the museum’s security system to short-circuit. Tony then levitates the gold bricks and sends them outside to a car, where Sickle awaits. Tia arrives and notices Wedge drag Tony into a car with Sickle, Gannon, and the gold. In pursuit of Wedge’s car, Tia jumps into Yoyo’s van with the Earthquake gang and tricks Yoyo into following Tony by advising that he is another truant. Yoyo delights at the prospect of bringing so many truants back to school and speeds after Wedge’s car. Controlled by Gannon, Tony sends obstacles into Yoyo’s path. Although Tia tries to thwart Tony’s efforts with her own powers, Yoyo is blinded by a burst of light that Tony sends his way and crashes. Back at the hideout, Tia uses telepathy to contact Tony, who leads her to Gannon’s lab, where she is captured and drugged. When she regains consciousness, Tia finds herself tied to a table but uses mind control to send Gannon’s pet goat, Alfred, to the Earthquake gang’s hideout. Gannon hatches a plan to take over a plutonium plant using Tony’s powers, while the goat locates the Earthquake boys and leads them back to Gannon’s lab. At the plutonium plant, Gannon uses Tony to deactivate a cooling device, then threatens the scientists who run the plant that he will let the plutonium overheat, causing massive destruction, unless they pay five million dollars, provide him with a getaway jet, and publicly announce that Gannon has achieved mind control. After hearing about the incident on the radio, Tia uses her powers to fix Yoyo’s van and convinces him to drive her and the Earthquake gang to the scene of the crime. Once there, Tia determines the location of the cooling system and finds Tony and Gannon. Tia turns the cooling system back on, but, using Tony, Gannon turns it off again and sends heavy objects flying in Tia’s direction. Although Tia worries that her brother has turned against her, she finally realizes that Gannon has gained control over his mind. Tia summons her powers to destroy the device and removes the chip behind Tony’s ear, bringing him back to normal. Together, Tia and Tony levitate Gannon, Wedge, and Sickle, leaving them stranded on a hanging rafter, high above the ground. With Yoyo as their chauffeur, Tony and Tia return to the Rose Bowl and meet up with Uncle Bene. The Earthquake gang bids the siblings goodbye as they fly off, and Yoyo finally convinces the boys to go to school.