The War Zone (1999) on Netflix

Tom (Freddie Cunliffe), an alienated 15 year old boy, finds the that opportunity for close observation of his father, after their move from London to rural Devon and the birth of a new baby, reveals a world run through with darkness and pain. Tom is unable to reconcile the life he's known what he sees with his own eyes, and blames his 18 year old sister, Jessie (Lara Belmont). Both Tom and Jessie struggle to find some path to truth and sanity as the human forces around them work in polarity with their isolation to either assist them, or destroy them.