Whilst exploring deep space, a meteor strikes Cosima and Dad's ship! After crash-landing on the unexplored planet of Proxima, Cosima makes a new best friend called Big Lizard.

When a pack of pesky, migrating trilobites overrun the ship, Big Lizard has to use a hidden talent to lure them away. But one little trilobite, Rex, decides to stay.

Searching for a vital part of the ship that was lost during their crash-landing, Cosima and Big Lizard find Dunk stuck on a beach. They use science to save the day and make a new friend.