Today is like any other day in Grover Cleveland Highís science labóany day in the Jurassic Era, that is! Doc, the school genius, has rigged up a tight little time machine masquerading as an exercise bike, all fine and good until pretty-girl princess Heather cops a ride and drags herself, Doc, and Lindsay Goldmanóa.k.a. teen superhero GoGirl!óback several million years to the dinosaur-infested jungles of the long-gone past. If being late for cheerleading practice isnít enough of an annoyance, try ditching a hungry T-Rex! And where did those alien spaceships come from?!