Spending their summer vacation at Grandpa’s house doesn’t turn out the way Emily, Jack, and Mary expect. Grandpa’s lifelong dream is to play the drums in his favorite band: The Fossils. That’s why he invents a time machine and travels back in time. The kids receive a message saying Grandpa has lost his time machine somewhere in the past and is unable to return to present time. It’s up to them to go and save him. The kids travel through the 60s, 70s, 80s, and 90s looking for Grandpa.