Ernie, Julia and Max accidentally start a time-machine while playing in Max's father's workshop and are transported back 65 million years where they are adopted by a doting dinosaur mom, Tyra, and a rambunctious dinosaur brother, Dodger. Meanwhile, their parents plot their rescue, but if they want to make it back home they must avoid evil dinosaur rivals and rely on the help of Tyra and Dodger - after all, family isn't always just the one you're born into!