When eleven-year-old Connie is sent to live with her eccentric aunt by the sea, she’s not expecting anything great—not to make friends with Col, the coolest guy in town, and certainly not to discover that mythical creatures still exist, that an ancient society has protected them for centuries, and that a dark and treacherous force is lurking in their midst.

Magical Mallins Wood is under threat from developers. Unknown to everyone but the members of the top secret Society for the Protection of Mythical Creatures, the wood is the home of the last gorgon, a creature so deadly she can kill with a look. Col's difficult mother is the gorgon's Companion - a human with a special bond with the gorgon - and she's determined to save it. So determined, that she'll allow the evil shapeshifter Kullervo to help her, even if it means having to sacrifice her son to him. But Kullervo wants more than to help the gorgon. He wants universal power, and he needs Col's best friend Connie to get it. Col's mum tells Col that she wants to meet this powerful girl. But is it a trap? And, if so, who is the hunter, and who the hunted?

The clock continued to tick calmly in the hall, out of step with the stormy sea of panic surging inside Connie. She could make no sense of this. How had she ended up on the beach? She felt a hum in her bones as if she had been meeting with some powerful creature. But what beast or being had the power to draw her out of her house without her knowing about it? And what had happened when they were together? Thirteen-year-old Connie Lionheart is the only Universal Companion, able to communicate with all the mythical creatures hidden in our world. She is the most important member of a secret society sworn to protect the bonds between humans and creatures. But her power brings great responsibility and great danger.

It's a long hot summer. Temperatures are soaring and a strange creature has been spotted on Dartmoor. Connie Lionheart and her friends soon discover that the creature is a chimera. When it attacks Connie, leaving her gravely wounded, Col and Rat must rescue her from she needs treatment beyond the knowledge of mortals. But a weakened Connie is easy prey for the evil shapeshifter Kullervo. He believes that, finally, the time is ripe for him to seize her Universal power, gather his army of mythical beings, and wipe out humanity. The battle between him and Connie will be a fight to the death. And the prize will be the future of mankind.