Deep Blue

Deep Blue is the second episode of the third Common Series.

Synopsis
"It's smart, it's vicious... and it's big!" - Cpt. Seamus Tersa

A rapidly growing heat signature under Antartica has been found a team of underwater explorers have gone to investigate the source. The Doctor, Amy and Rory find themselves on board and they soon find that there is something deep within the vast, cold and dark waters of the Southern Ocean and it is not friendly.