The Swarm

Amid disturbing events in the world's seas, scientists realise that an unknown species could threaten humanity. From the executive producer of Game of Thrones. (S1, ep 1)

As whales attack tourists in Canada and lobsters turn deadly in France, a scientist discovers aggressive worms multiplying at speed. (S1, ep 2)

Venice sees an unprecedented plague of jellyfish, while in Canada, researcher Anawak is getting to the bottom of whale attacks. (S1, ep 3)

Cecile recommends stopping fishing off the coast and warning the population against using tap water, while the worms are investigated more closely. (S1, ep 4)

Johanson travels to Shetland, while the team receive a warning that a tsunami is heading for the area and the Atlantic coast of northern Europe. (S1, ep 5)

Johanson suspects that an unknown marine intelligence is behind all the results, and plots to contact the life form with a research mission. (S1, ep 6)

The expedition to study the Yrr sets out for the Arctic. During a trip by submarine, Charlie Wagner observes a magical sight. (S1, ep 7)

With humanity's future at stake, the team butt heads on what to do on the boat. In a desperate situation, Charlie makes a radical decision. Season finale. (S1, ep 8)