Following the sudden death of their mother, twins Theo (Thomas Cameron) and Rachel (Sophie McBride) are sent to live with their aunt and uncle in Auckland, New Zealand. While exploring their new surroundings, the twins soon learn about the Wilberforces, a strange, reclusive family living in a dilapidated house on the islands outskirts.
For as long as they can remember, the twins have shared the power of telepathy, and an apparently chance meeting with the enigmatic Mr. Jones (Sam Neil, Possession) sees them come to learn the true extent and purpose of their gift.
Mr. Jones, the twins discover, is from an alien race known as "The People Who Understand." Through Mr. Jones, the twins learn that the Wilberforces are actually an alien race themselves, but unlike Mr. Jones's race they are intent on destroying all life on Earth. Even worse, the Wilberforces have allied themselves with the "Gargantua," a devastating race who, thanks to Mr. Jones's intervention years ago, have been trapped beneath seven of Auckland's volcanoes. However, it seems the Wilberforces have awoken the Gargantua from their slumber, and are mere days away from the great beasts rising up and destroying all life on Earth.
With time quickly running out, the twins must learn to harness their burgeoning powers, as they alone must stand against the Wilberforces to save the world.