Felt is a thief without money. Her younger half-sister, Cassie, suffers from a chronic illness and treatment costs have just gone up. The only job that offers the coin she needs involves breaking into the hermetically sealed sanctum of White Candle, the city's foremost magic guild.

Trying to break into such a place would be dangerous enough under regular circumstances. Trying to do so when all of White Candle's magistrae recently entered that same sanctum, never to be heard from again, makes it suicide. Felt cannot refuse, however, as her new employer has threatened to arrange for Cassie's treatments to halt entirely.

The job is a disaster. A mysterious group assaults the sanctum that same night, leaving behind several bodies and Felt unconscious. She is arrested by the Crown, who later realize she had nothing to do with the attack. They promptly draft her to aid them in the investigation, suspecting that her shady employer knows more.

Felt now has to balance safeguarding Cassie with assisting the investigation as various forces in the city begin to make their own moves, each seeking to benefit from or solve the mystery of the White Candle's disappearance.

And the sanctum's seal is weakening.