Josh Higgins has an alien gizmo that lets him think his way to other planets—and he does NOT want to use it. But his sister Maggie won't stop bugging him, so he agrees to an off-world vacation. Josh dreams up a planet full of blue oceans, white beaches, and sunny weather. And he prepares for everything...well, almost.

A parade of cranky creatures soon spoils Josh and Maggie's perfect getaway—including a one-horned beast, a sharp-toothed sea princess, and a two-tailed monkey. The planet's locals just can't get along, and Josh and Maggie find themselves caught up in the squabbling.

As the Earth kids rush from one danger to another, will they discover a way to keep the peace? Or will Josh and Maggie become prisoners of the not-so-perfect planet?