Corrupted doesn't always mean wicked.

After sixteen-year-old Ari Jones overhears a nurse forbidding roses, she's determined to rid herself of anxiety-induced hallucinations. That means burying her panic attacks on the compost heap. But Samael Lowood---a ghost with a smile like winter---refuses to cooperate.

When a demonic mailman appears in Ari's bedroom and offers a deal---the return of her father in exchange for a long-lost Nanorian---Sam opens a doorway to an afterlife for corrupted souls. There, surrounded by snow-dusted roses and eternal night, he tells Ari about the Nanorian: a demon's heart stolen over a hundred years ago.

With Sam's help, Ari sets out to find the Nanorian and rescue her father. But even gentlemanly ghosts have agendas. When Ari learns the Nanorian grants the innermost desire of whomever knots it around their neck, she realizes the wrong choice could be as devastating as a killing frost. Though Sam claims he wants the Nanorian destroyed, his story feels off. Either he's lying, or he's believed a lie for over a century.