The Gathering Darkness by Lisa Collicutt

They say "third time's the charm", and for sixteen-year-old Brooke Day, they had better be right. She’s been here before – twice in fact – and an evil demon-witch wants her dead a third time.

When Brooke is forced to leave Boston for the small town of Deadwich, she thinks her life is over. Before long, her new friends start acting strange – downright evil. Worse, the nightmares she’s had her whole life are becoming reality.

Enter Marcus Knight; popular, hot, and the only person Brooke can trust. Not to mention, they’ve shared the same nightmares. With the discovery of an ancient Celtic amulet, Brooke and Marcus unravel the secrets of her past, in search of the key to her future.

As the equinox approaches, darkness and light merge for the first time in a century, soul-mates reunite, and magic awakens!