Nell, Simon, and their boy Art are ready to welcome friends and family for what promises to be a perfect Christmas gathering. Perfect except for one thing: everyone is going to die.

Eve’s husband has been killed in Afghanistan. She takes her young son to a Suffolk beach house on the edge of the North Sea to grieve. But someone else is in the house grieving her loss from another war.

Two young boys playing in the woods discover the entrance to a military bunker undetected since World War II.