Grace Graham accuses her father of making poor choices that caused her mother’s death. But Grace is soon on the receiving end of those accusations when her decision not to have her son immunized puts other children in danger, including her own niece.

When Annie Fletcher returns to Charleston to see her younger sister, Sarah, receive her master's degree, she finds herself riding in the back of an ambulance, watching helplessly as Sarah fights for life. During the ride, Sarah appears to talk to someone who is not there, humming a melody Annie has never heard before. Neighbor Ethan McKinney is there to lend a shoulder when Sarah unexpectedly dies.