England, December 1926. Although her personal life is in tatters, the famous writer Agatha Christie decides to leave everything behind to help unravel an unsolved murder committed on a train six years ago, unable to imagine the disproportionate consequences that such a selfless act will cause.

On an archaeological dig in Iraq, author Agatha Christie uncovers a series of murders.

As bombs fall on London, writer Agatha Christie decides it is time to kill off her most famous creation.