The reserved elf Lyell Blackfletch is an ambassador for his people - and the holder of a dark secret. Plague is spreading among the human race, with the fire-loving dwarves already driven to the edge of extinction. Only the human Fiorella is close to finding a cure for the sickness, and with her death it is up to her friend Lavender the gnome to deliver it to her people in the steam-powered city of Vaporcitta. Naïve but rebellious, Lavender chooses to place her trust in Lyell - but is her confidence in the cold-hearted elf misplaced? With the cure stolen and a secret genocide uncovered, they must both make a choice - but it may already be too late.