Sin is the only female Seminus demon alive who is also a master assassin. She has never counted on anyone but herself, not even her twin brother Lore. Sin also has a raging libido she controls with the tattoo on her right arm called the dermoire. Though she must stay ruthless and strong, she has been plagued by guilt after unleashing a virus that is killing wargs, better known as werewolves. If she and her brothers who work at Underground General, a supernatural hospital, can't stop the plague (named Sin Fever), it will destroy the wargs and may threaten other creatures, including humans.

Paramedic Conall Dearghul is a dhampire-- half-werewolf, half vampire. He and Sin acted on their physical attraction once but as soon as Sin was done with him, she pushed him away. Conall is more than bent out of shape over Sin treating him like dirt, but he can't stop thinking of her. He may just get more than he bargains for when he and Sin team up to stop the virus.

Not only do they have to stop this deadly virus, but Sin has to stay on her toes since she has been marked for death. And Conall is being forced to take his seat on the Warg Council and fulfill his dhampire duties. Soon he and Sin are on the run, hiding from those that want to eliminate them both. Sin refuses to become a victim. Conall wants her to lean on him for support. He wants her to learn that it's alright for her to feel and love.

SIN UNDONE is the final book in Larissa Ione's Demonica series and fans will not want to miss it. Sin is haunted by both her past and present, and has no choice but to become cold-hearted and sometimes cruel in order to survive. When Conall comes into her life and forces her to reflect on her actions, she begins to forgive herself. She has a strong support system in family, friends, and even Conall who wants her as his own. Conall doesn't want to own Sin or force her to please him for his own gains. As they come to rely on one another, he sees how special she is. Sin, in turn, opens her heart to him.

Larissa Ione can write some great action. Her sex scenes are some of the hottest I've read in a paranormal romance. You can practically taste the lust and desire Conall and Sin have for one another. These two have great chemistry even as they hurl insults at one another.

SIN UNDONE doesn't disappoint and makes way for yet a new set of characters and books, in her soon to be released Lord of Deliverance series.