Kell never wanted to climb. Then her sister Eira starts dying of a sickness no healer below can touch, and the only cure is a god's domain eleven floors up the Godspire. So she climbs. The first floor gives her doors no lock can hold. The second gives her the tide. Every floor makes her more than the girl from the Underspire, and the ledger is honest: each floor gained is a measured piece of her own self spent, posted in the same breath as the power.

Then Kell meets a climber coming down from the top, ruined and hollowed, and begins to suspect the ascent costs far more than the ledger admits. The higher she climbs, the less of the girl who loved Eira will reach the summit to use the cure.