"A desperate call for help interrupts holiday celebrations at the Bureau of Balance, and sends Taako, Magnus and Merle on a high-stakes mission to find and reclaim a fourth deadly relic: a powerful transmutation stone, hidden somewhere in the depths of a floating arcane laboratory that's home to the Doctors Maureen and Lucas Miller. An unknown menace has seized control of the stone, and is using it to transform the lab into a virulent pink crystal...

"Our boys have gone full-time at the Bureau of Balance, and their next assignment is a real thorny one: apprehending The Raven, a master thief who's tapped into the power of a Grand Relic to ransack the city of Goldcliff. Local life-saver Lieutenant Hurley pulls them out of the woods, only to throw them headlong into the world of battle wagon racing, Goldcliff's favorite high-stakes low-legality sport and The Raven's chosen battlefield. Will the boys...