Pete and Steve are sent to a Renaissance Faire to search for an artefact that's making horseless chariots and life-size chess pieces come to life, while Claudia's desperate attempt (with Myka's help) to remove the effects of the music box artefact from her sister in order to revive her have unintended consequences.

An old enemy returns and attempts to move the Warehouse, and plans to use Claudia's sister to do it.