Time Travel Warriors

Although things happen to the Worthington family, Luke and Scott never imagined in a million years that they'd ever create a time-travel machine. But they have, and now their adventure begins.
Hurled back and forth in time, they come face-to-face with ferocious dinosaurs, fight gladiators in ancient Rome, and fly spaceships in the distant future.
They are helped in their struggle to return home by Percy and Troy, elite time-guardian warriors. And all they have to do is find the mythical Crystal of Time, capture an evil time guardian, and defeat a skeleton army that cannot be killed.
No pressure then.