The common perception of the UK's seas is that they are dark, cold, and dirty, but the reality is very different. Following the success of Oceans, Secret Seas shows that Britain's native waters can be every bit as dramatic, colourful, and surprising as those anywhere else in the world and provide a home to extraordinary creatures, spectacular seascapes, underwater cities and a source of food. The series also examines the threats facing these waters and reveals the steps that are being taken to protect them.