Even amongst the Eldar, the Harlequins are a capricious, mysterious breed. When a troupe of these deadly warrior-performers discovers a dead Craftworld festering in the webway, they are determined to find the one responsible and exact punishment. Using the ancient craft of their Shadowseer, the trail of destruction leads the troupe to the Sable Marches, a fringe realm of the Dark Eldar. With several possible suspects of this heinous crime, the Harlequins decide to draw out the guilty one by staging the Masque of Vyle for the archons, a performance that will expose the truth and lead, fatally, to the perpetrator.