Holden told Olivia it was only a matter of time before Hell came for them. After all, one doesn't just walk away from the life he lived unscathed, but the longer Hell waited, the more Olivia let down her guard. She believed maybe happily ever after was possible—he knew it wasn't.
But when Baker shows up beaten and bloody on their doorstep with a message, all hope evaporates. The jinn make Holden an offer he can't refuse: convince Olivia to free them all and the jinn will fight Hell alongside them. However, if their past has proved anything, it's that the jinn cannot be trusted. When Olivia starts hearing a voice that no one can identify and Baker isn't acting like himself, he is forced to make a decision.
With Heaven staying hands off, Holden considers accepting the jinn's offer behind Olivia's back. One thing is clear, with their lives and the lives all those they hold dear at stake, something has to be done. If it were as easy as Holden going back to the jinn, he would do it in a heartbeat, but Hell wants more than his soul this time—they want Olivia's too.