2025 · 1 Season ·Ended★ 7.1 ·United Kingdom · EN· BBC One

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.

Episodes

S01E017 Dec 2544m

Homo Aqua

Barclay's ordinary life becomes a world of terror when an ancient species rises from the sea. As UNIT fights for control, the summit on the Thames reveals terrifying secrets.

S01E027 Dec 2548m

Plastic Apocalypse

Barclay becomes humanity's ambassador when the mysterious Salt emerges from the Tank. But his family's life is torn apart when Salt wreaks revenge upon all mankind.

S01E0314 Dec 2545m

The Deep

Barclay makes a terrifying descent into the world of Homo Aqua. Back on the land, Kate stands alone as Downing Street conspires with the army to change the course of the war.

S01E0414 Dec 2546m

The Witch of the Waterfall

Barclay and Salt go on the run in a war-torn London as UNIT reels from disaster. But when Tide threatens the land and Gunsberg advances his plans, the Severance schemes demand blood.

S01E0521 Dec 2554m

The End of the War

Barclay stands alone, Salt is lost, UNIT is powerless, and the oceans rise as the war reaches its climax. While traitors conspire, can Barclay find Salt before it's too late?