Zack and his father are invited to join the Nebulon Navigators as they set out to return a lost baby pterosaur to the Prehistoric Planet, where Zack sees animals and plants he had only read about in books.
On the planet Nebulon in 2120, Zack joins his school's Explorer's Club and visits Juno, a planet made of crystals, but he is less than thrilled when he is partnered with the class bully.
Zack is shocked to find a large, green, six-eyed creature sitting in his place at school one morning, but soon learns that he and the "monster" have a lot in common.