Quentin James and his friends are off to the Loch of Arthur for a holiday. Whilst having a fantastic time, swimming and hiking, they explore a secret passageway which leads to an old abandoned castle built into the cliffs.
That's when things start to get really exciting.
Capture, Escape, Enemy I.O.N Agents, Treasure, Merlin and having to dress as a girl! Quentin faces all these challenges and more in his second most dangerous mission yet.