Phantasma by Kaylie Smith

Welcome to Phantasma. There are only two rules to the game: stay alive. and don't fall in love. 

When Ophelia's sister disappears, there is only one way to save her. Ophelia must enter Phantasma, a deadly contest inside a haunted mansion, and claim its prize- a single wish. 

Phantasma is a maze of twisting corridors and lavish ballrooms, of demons and temptations. Ophelia will face nine challenges, each more dangerous than the last. There can only be one winner, and the other contestants will stop at nothing to eliminate their rivals. 

Every day the house creates new monsters. But just as Ophelia's fears threaten to overwhelm her, a mysterious stranger offers her a bargain. 

Charming, arrogant and infuriatingly attractive, Blackwell claims he can guide her through the lethal trials ahead. All he asks in return is ten years of her life. 

Ophelia knows she shouldn't trust him. Blackwell doesn't seem dangerous, but appearances can be deceptive. Worse still, she feels a dark and irresistible attraction drawing them closer and closer. 

Her life is on the line. But in Phantasma, the only thing deadlier than losing the game is losing your heart...