Seventeen Again (TV)

When the Donovan family moves from California to Connecticut, 17-year-old Sydney finds it's not easy being in a new town away from her old friends, but her 12-year-old genius brother Willie is happy as long as he can tinker in his lab with his increasingly complex experiments. Willie is convinced he can defeat the aging process, and while devising an experimental anti-aging formula, he accidentally spills some on a bar of soap. When his grandmother Cat mistakenly uses the tainted soap, she's transformed into a 17-year-old. Her ex husband Gene follows suit, and is also returned to his teenaged self.