Reapers - Unseen Things, #19

When the reaper drones showed up at the party to kill Diedre so they could reclaim her energy and take it back to Purgatory, she and Logan had go on the run, hopping from dimension to dimension in an effort to try to stay one step ahead of them while the folks back home work on a way to rectify the situation without leaving all of the energy forms on Purgatory stranded there for all eternity. In their search for answers however, they make some incredible discoveries, not only about the dimension of Purgatory itself, but also about the root cause behind Diedre's psychotic behavior in her former life.
Also, when Derek pays himself a visit from the future, he learns that their attempts at finding a solution to the Diedre situation appeared to have worked at first, but things ended really bad for them shortly thereafter. Now they have to think outside the box to come up with a new and unique way of solving the problem that they wouldn't have otherwise considered, because if they don't, then some people that they care very deeply about are going to end up dead, while others will have a falling out that will cause them to go their separate ways.
Finally, while out on the run from the Reaper drones, Logan and Diedre's feelings for one another continue to grow, but can Logan resist temptation so that he doesn't end up hurting Darla and destroying their marriage? Derek isn't so sure, and every time that Logan returns and the others fail to catch him so they can swap out who's protecting Diedre, his anger continues to grow. When he starts taking that anger out on the family however, Jarrod is forced to give him a harsh reality check to bring him back to his senses.
Reapers is book 19 of the Unseen Things series.