A second mystery for thirteen-year-old Agatha Oddly – a bold, determined heroine, and the star of this stylish new detective series.

Agatha Oddlow's set to become the youngest member of the Gatekeepers' Guild, but before that, she's got a mystery to solve!

There's been a murder at the British Museum and, although the police are investigating, Agatha suspects that they're missing a wider plot going on below London – a plot involving a disused Tube station, a huge fireworks display, and five thousand tonnes of gold bullion…