Zero. The Skulls, #6

Zero's foolish mistake could get them all killed. Ten years ago, Zero tortured a man for killing his friend. Then Zero set the building on fire, to kill the man and torch the evidence. When he left the burning building, he thought the man was dead-but he wasn't. Now, Zero's enemy is back, and the game of cat and mouse is about to start. Prue has loved Zero for a long time. He was her brother's best friend, and he's protected her through thick and thin.
After she got shot by his enemy, he's there to save her life. The ghost of his enemy lurks everywhere, hitting out when they least expect it. No one can stop him, and no one can save them. One by one, Zero's friends fall, and he's helpless to stop it. His enemy has all the control, and there's nothing he can do. The only one he can trust is Prue. She's been with him through everything, and now it's time for them to take the man responsible for tearing their lives apart and put him in the ground.
How much can Zero sacrifice before it's too late?