Detective D. D. Warren is hard to surprise. But a lone woman outside D.D.'s latest crime scene shocks her with a remarkable proposition: Twenty-seven-year-old Charlene Rosalind Carter Grant believes she will be murdered in four days. And she wants Boston's top detective to handle the death investigation. It will be up close and personal. No evidence of forced entry, no sign of struggle. Charlie tells a chilling story: Each year at 8:00 p.m. on February 21, a woman has died. The victims have been childhood best friends from a small town in New Hampshire; the motive remains unknown. Now only the last friend remains to count down her final hours. But as D.D. quickly learns, Charlie Grant has been preparing, and she doesn't plan on going down without a fight. As D.D. tracks a lone gunman who is killing pedophiles in Boston, she must also delve into the murders of Charlie's friends, seeking the elusive insight into who might be stalking and killing these childhood playmates, in the hopes of preventing whatever might come this February 21. Just how much can she trust Charlie Grant, a woman who by her own admission can outshoot, outfight, and outrun anyone in Boston? Is Charlie truly in danger, or is she hiding a truth deep within her that may turn out to be D.D.'s biggest surprise of all?