Episode PremiereApril 13, 2013
Show Period2006 - Now
Production CompanyBBC Worldwide Productions, CBC
Cast and Crew
The Doctor and Clara land on a damaged Russian Submarine in 1983 as it spirals out of control into the ocean depths. An alien creature is loose on board, having escaped from a block of Arctic ice. With tempers flaring and a cargo of nuclear weapons on board, it's not just the crew but the whole of humanity at stake!