Five thousand years later after a catastrophic event rendered the Earth a ticking time bomb, the progeny of a handful of outer space explorers--seven distinct races now three billion strong--embark on yet another audacious journey: to return to Earth.

This time ten-year-old Starr and her family are exploring Venus, mostly by remote controlled probes, but the two children they are escorting seem more interested in a competition to show how much they know, and as usual Starr's older brother Apollo is not much of a help in coping with their bullying.