Skye's human half-sister has disappeared, drawing him into contact with his estranged human mother who is convinced Skye is to blame. Adding to Skye's problems is an unfortunate encounter with his father, the Emerald House Ambassador, and a malicious gargoyle who insists that Skye locates his missing stone of power -- itself a dangerous magical relic that will warp the humans who come in contact with it. When another sibling disappears, there is no doubt this trouble is aimed straight at Skye.