After leaving Earth, now devastated by an alien attack, and exploring the galaxy, Clover Martinez and her fellow teen survivors return home to find crystal formations in the soil that are threatening to destroy the planet, and a colony of survivors who are not who they seem.

Clover Martinez and the Last Teenagers on Earth are busy exploring the galaxy after leaving earth behind...even if they are homesick. So when their ship receives a distress signal from their former home, they hope against hope that it means that there are other survivors. But as soon as they arrive, they realise something's deeply wrong: strange crystal formations are taking over Earth's soil and threatening to destroy the planet.

Seeking the origin of the formations, the group discovers a colony of survivors hidden in the mountains. Relief gives way to panic as the teenagers realise these survivors aren't who they seem…and Clover and her friends might not be able to escape.