Former 'street rat' Briar leads a comfortable life at Winding Circle Temple, learning plant magic from Rosethorn. But street kids are still his friends, and when one of them gets sick, she turns to Briar for help. When her disease proves beyond even Rosethorn's power, Briar realises that all of Summersea is in danger. As the mysterious illness spreads, Sandry, Daja and Tris join Briar and their teachers to fight the epidemic. But just as the situation improves, the unthinkable happens. Will Bria