Months after escaping the horrifying creatures living in the London underground, Lexi Keely and her small group of survivors find themselves with new challenges as they make their home in Dunsbrough Castle in the South-East of England.

Technology has virtually disappeared.

Food is in short supply.

The gloom brought about by the never-ending cloud cover caused by the asteroid’s impact makes growing anything almost impossible.

A chance sighting of sheep in a field across the mighty Thames River sends the group in search of protein. Arriving on the southern bank, the sheep are not the only wildlife they encounter.

Whilst examining the remains of several of the terrifying aquatic humanoids, a lone survivor of the creatures’ attack stumbles in the group and fuels the group’s nightmares once more.

Drawn to the castle, the creatures invade and kidnap one of Lexi’s group.

Steeling herself, Lexi embarks on a journey to exact revenge and rescue her friend.