Eighteen-year-old Thalia survives as a grave robber in the vast necropolis outside Aegiros, a thriving city where the dead outnumber the living—until she discovers a powerful relic that opens a doorway between the world of the living, and the Underworld itself.
Captured and sentenced to death, Thalia receives unexpected mercy from Prince Marius, the kind-hearted heir to the throne. But when Marius falls victim to a poisoned blade, Thalia is forced into an impossible bargain: descend into the realm of the dead to find a cure, or watch the only person who ever showed her kindness die.
In the Underworld, Thalia finds an unexpected ally in Kassian, the realm's mysterious guardian who warns her that every journey between worlds comes with a terrible price. As she races against time, Thalia is caught between her growing feelings for the noble prince above, and her dangerous attraction to Kassian below.
