Two police inspectors track down a mysterious criminal who signs his crimes with a fiery triangle. When they have just discovered an accomplice, one of the police officers, in love with the young girl, is shot dead. His colleague will then have only one goal in mind.

Eva lives in the sinister Tower with her father, a mad inventor, and her grandfather. The aviator Wilfred Durian and his lovely wife live nearby in the town. But Durian's famous flight across the Australian desert was not all it seems... and when his 'dead' partner Arved Holl is rescued by Eva and comes to claim his former fiancée's hand, the whole house of cards is about to come tumbling down. Meanwhile, Eva's own family history is not quite as she had always believed...