Twins Rachel & Theo Mathieson are saved from death by a kindly and mystical stranger. Eight years later when they visit Auckland they find they have been chosen for a momentous task against the forces of evil.
A sightseeing trip to Auckland's dominant volcanoes brings further evidence that the twins have a dangerous mission. Is Mr. Jones' guardianship enough to protect them from the sinister Mr. Wilberforce and the slimy creatures which lurk in the lake?
Rachel's sleep is disturbed by a telepathic cry for help. Mr. Jones' voice seems to drift through the fog from the weird Wilberforce house and the twins steal through the night to his rescue.
Rachel & Theo learn from Mr. Jones about the strategy they must employ if their planet is to be saved. They discover the truth of Mr. Jones' warning "Any Shape, Any Form".
Time is running out as Rangitoto is ablaze and crimson. Ricky is left as a decoy as the twins and Mr. Jones struggle towards their final goal, not realizing just how ruthless the aliens are.
