Every four years, someone dies on 29th February.

When a woman is found dead on her birthday, Detective Ellie Monroe is called to the scene. At first, it seems like a tragic coincidence.

It isn't. As Ellie digs deeper, she uncovers a pattern stretching back years. Each victim shares one chilling detail: they were all born on the same date.

But this isn't random. Someone has been waiting. Watching. Planning.