Early 20th-century adventurers find themselves fighting for survival after their hot-air balloon crashes into a remote part of the Amazon, stranding them on a prehistoric plateau.

Megan's world is turned upside down when she hears her calm life with her little brother and single mum is about to change. She hears she's soon to have a stepfather and a stepsister. Megan thinks they're a bit weird and is determined to stop the wedding. She discovers they're actually even stranger than she thought - they're from another planet.