When jewels became lethal in the London of 1912, both River and the Doctor turn up to find out why. A mystery takes them centuries into the past, and onto the high seas, where a superstitious crew edges towards mutiny. The star-crossed couple are about to find out that, while gemstones inspire jealousy, love can be the deadliest treasure of all… Cast: David Tennant (The Doctor), Alex Kingston (River Song), Joe Jameson (Captain John Bickell/Joseph/Landlord), Barnaby Kay (Gerrard Pulman/Foreman), Anjli Mohindra (Omara/Barmaid/Franny), Joe Sims (Abe Porter/Mr Chauncey/Pat). Other parts played by members of the cast.