After first grade teacher Terra Franklin witnesses the death of her student, she’s consumed with guilt and desperate to put her trauma behind her. And she’s succeeding—until she receives a series of threatening phone calls accusing her of murder.

The calls plunge Terra into a state of constant anxiety and dread—and convince her that the caller is Sherri Nelson, the aggressive and overprotective mother of Terra’s deceased student. After all, Sherri blames Terra for her son’s death—and she’ll do anything to make the frazzled woman pay.

Days later, Terra’s harassment rapidly escalates from hostile phone calls to shattered windows and menacing notes left inside her house. Terra is convinced that Sherri has invaded her home. But when she learns that Sherri’s alibi is ironclad, her anger quickly morphs to confusion—and fear. After all, could Sherri really be responsible for the tall, horned figure that begins to appear in Terra’s bedroom at night? Or what sounds like the heavy clomping of hooves in her basement?

As Terra uncovers more about Sherri and the grieving mother’s dark secrets, she is forced to question which horrors are real and imagined, human and inhuman. And the malicious presence looming over them threatens more than just her peace. More than her sanity. Because it’s growing.

And it’s stronger than either of them could ever imagine.