When a night of babysitting turns fatal, a girl burdened with survivor's guilt becomes increasingly convinced that someone is responsible for the gas leak that killed her family member—and that she was the intended target all along.
Ella wishes that she could do something more fun on New Year’s Eve than babysit, but lately her life has taken a scary turn with a diagnosis that she is trying her best to ignore. So after she barely recovers from another paralyzing migraine, Ella arrives late to her aunt’s house for babysitting. 
But when nobody answers the door, she knows something isn’t right. Breaking in, she finds her cousins unconscious on the floor. And Aunt Julie is dead. Ella is barely able to rescue them from the house before she collapses into the snow. 
When investigators discover that the cause of death was from a gas leak, a small voice in the back of her head keeps reminding Ella that it could have been her—not Aunt Julie—inside that house. Ella is determined to find out what really happened to her aunt, but her family is so sure it was an accident. After all, Ella’s paranoia must just be a side effect of her diagnosis—a diagnosis that makes everyone tiptoe around her.
As deadly lies begin to seep through the cracks of the investigation, Ella gets the feeling that the gas leak might not have been an accident—and that someone might be out to kill her next.