On a lavish yacht for an assignment, a journalist sees a passenger go overboard. But when no one believes her, she risks her life to uncover the truth.

When a fearsome and ancient species emerges from the ocean, dramatically revealing themselves to humanity, an international crisis is triggered. With the entire population at risk, UNIT step into action as the land and sea wage war.

An unexploded WWII bomb is discovered on a busy construction site in the centre of London. Chaos ensues as the military and police begin a mass evacuation against a ticking clock.