Death has always stalked single mother Allie Callahan. For the first time in her life, she has found a fragile sort of happiness living a quiet, peaceful existence in East Texas with her young son, Sammy, and her adoptive mother.

Still, Allie fears she may be susceptible to the same mental illness that destroyed her serial-killer mother and brother. She's haunted by the idea that she could become incapable of caring for Sammy.

When twelve-year-old twins Zoe and Carrie arrive on her doorstep late one night, their parents slain in a vicious double homicide, Allie’s strength and sanity are put to the test. What did the twins see on the night of their parents’ horrific murder? They are too frightened to say.

Soon faced with a series of menacing phone calls, a rising body count, and the pressure of keeping the girls and her own son safe, Allie fears she'll lose her mind—and her one shot at happiness—once and for all.