Mercy (The Guardians, #1)

Mercy is a sleepy town in Massachusetts. According to the locals it was founded by the survivors of the Salem witch trials. Olivia West hadn’t set foot in Mercy since the night her Father murdered her mother but when she unexpectedly inherits a house by the lake she has no choice but to return.
When the bodies of missing residents are discovered in the woods near her house, it becomes clear there’s a killer on the loose who seems to have taken an unhealthy interest in Olivia. Disturbingly the murders are almost identical to a spate of killings twenty years earlier which mysteriously stopped after her father’s arrest.
Olivia finds herself thrown into a world of murder and magic. She can no longer ignore her past but must discover what really happened the night her mother died. Theodore Beckett is a witch finder from seventeenth century Salem, pulled through time to help her. Together they must stop a murderer and uncover her family’s oldest and darkest secret, to prevent a demon from rising...and time is running out.