Book four of the Jack Mason Adventure series. After a series of fatal
bombings across London, Jack, Scarlet, and Mr. Doyle are drawn into
another baffling case: the reported sighting of a monster roaming the
city's underground sewers. Before they can investigate, the team must
travel to Spain to hunt down a group of terrorists. But just as they
close in, Jack and Scarlet are kidnapped. With their lives in perilous
danger, will Mr. Doyle find his young assistants in time? Back in
London, will the monster's true origins be uncovered before it too
wreaks deadly destruction across the city?