Dave Douglas is a district attorney who has just prosecuted a group of activists, led by Dr. Kozak who have broken into the pharmaceutical corporation Grant & Strictland after they accused them of animal experimentation while trying to find a Fountain of Youth. The activists have also stolen a sacred Bearded Collie from a Buddhist Sanctuary named Khyi Yang Po, a dog with a DNA mutation that allows it to live a very long life. After several failed experiments, the dog breaks out and is discovered by Dave's family, who name him Shaggy because of his appearance. Dave wants the dog out but winds up bitten by him. Dave soon begins experiencing dog-like traits and soon, turns into a dog entirely. Dave is later kidnapped by the same activists who were experimenting with the original Shaggy and his family along with Shaggy must rescue Dave and return him to human form so he can testify in court about Dr. Kozak and the activities of his activists.