Return from Witch Mountain

Return from Witch Mountain is a 1978 sequel to Walt Disney Productions 1975 film, Escape to Witch Mountain. It was written by Malcolm Marmorstein and is based on the novel by Alexander Key. Ike Eisenmann, Kim Richards, and Denver Pyle reprise their roles as Tony, Tia, and Uncle Benhumanoid extraterrestrials with special powers including telepathy and telekinesis. The two main villains are played by Bette Davis as Letha Wedge, a greedy woman using the last of her money to finance the scientific experiments of Dr. Victor Gannon, played by Christopher Lee.

Having spent a good deal of time enjoying the company of their newfound family and friends at Witch Mountain and intensively studying and practicing their supernatural powers, Tony and his sister Tia are in need of a vacation. Uncle Ben drops them off in their flying saucer at the Rose Bowl stadium in Los Angeles, California, after which the siblings quickly become separated from each other. A man named Dr. Victor Gannon Lee and his assistant Letha Wedge Davis happen to see Tony using his powers to save their henchman from certain death. Realizing that Tony has supernatural powers, Dr. Gannon drugs the boy with a tranquilizer shot and takes him back to their laboratory. There, Dr. Gannon successfully tests a new mindcontrol technology on him. Under its influence, Tony is completely hypnotized and does everything that his kidnappers want him to do, like stealing gold from a museum exhibit and stopping Tia from finding them. With Tony at his robotic bidding, Dr. Gannon hopes to achieve recognition within the scientific community and worldwide power, while Letha merely wants a return on her investment.Tia uses her telepathic powers to locate Tony. She gets additional help from a group of wouldbe toughs whom she comes across, called the Earthquake Gang, and a hapless truant officer Mr. Yokomoto whom the toughs call YoYo to find her brother, and foil the villains nefarious plans. ........

Source: Wikipedia