When the Titanic sinks it takes with it the crime scene, the witnesses and possibly the murderer.

The Titanic's last stop is at Queenstown, Ireland, where seven first-class passengers disembark.

Soon after continuing its voyage, the body of a man linked to the doomed liner is fished from the water – murdered.

With the crime scene now at the bottom of the ocean, District Inspector Lorcan O'Dowd's only clue to the identity of the killer is through the seven passengers.

He follows their trail to London and China, slowly piecing together the life of the dead man. A woman is charged with murder, but O'Dowd isn't convinced. He's determined to find the real killer.