Resonance - Erica O'Rourke

As a Walker between worlds, Del is responsible for the love of her life--and the fate of millions--in this thrilling sequel to Dissonance. As School Library Journal raves, "O'Rourke brilliantly builds an intricate and complex alternate science-fiction universe...fans will be longing for the next installment."
Del risked everything to save Simon, and now he's gone, off in another world with no way for Del to find him.
She's back at the Consort--training to be a Walker like everyone in her family. But the Free Walkers have other plans for her. This rebel group is trying to convince Del that the Consort is evil, and that her parents are unwittingly helping the Consort kill millions of people. The Free Walkers make Del the ultimate promise: if Del joins their fight, she will be reunited with Simon.
In agreeing, Del might be endangering her family. But if she doesn't, innocent people will die, and Simon will be lost to her forever. The fate of the multiverse depends on her choice...