In the fourth of these thrilling fantasy adventures, the whole existence of Perex is threatened when the creepy Derek Frimp sends himself to the microscopic world. Pursuing him, Abi arrives in the remote, exotic land of Prishifi, where Frimp is sentenced to death and Abi embarks on a desperate bid to save him. Meanwhile, Jake lands in his beloved Shemmara, only to become the target of a would-be murderer. But when he travels to Prishifi, he finds his troubles have only just begun...