Thanatos by Felicity Heaton

Thanatos, god of death, has a mission: scour the unknown realms of the Underworld and retrieve the only daughter of his god-king, Hades. Murdered six centuries ago and her soul captured before it could pass on, she now falls under Thanatos’s domain. Armed with only a description of the location of her prison seen in a vision by her oldest brother, Thanatos has spent four years hunting for her, determined to complete his task and save her.

But when he locates Calindria, she’s not the delicate little girl he remembers—she’s a fierce, bewitching and beautiful warrioress who stirs unwanted feelings in his black heart and she’s on a mission of her own. Calindria, daughter of Hades, has a mission: escape her prison, hunt down the ones who murdered her twin brother, and then make her family pay for abandoning her. But the Fates have other plans, placing a distractingly gorgeous god of death in her path—a warrior who is determined to convince her that what she believed is the truth is in fact a lie.

In a realm that turns memories against them and where anything can be an illusion, can Calindria and Thanatos learn to trust each other enough to work together to escape the hellish domain, or will the darkest moments of their past prove too powerful to overcome?