London, 1888. Though Miriam Cromer has confessed to the murder of her husband's assistant, she is still confident of her acquittal. However, the jury sentence her to hang.

 Miriam then says her husband was the killer, but he has an alibi. Can Sergeant Cribb and Constable Thackeray discover what really happened at Park Lodge on that fateful day in March before it's too late?