The War Zone (1999)

Suddenly, moody 15-year-old Tom, and his 18-year-old sister Jessie find themselves relocated from the hustle and bustle of urban London to the sullen silence of wind-swept rural Devon, at a little but neat cottage in the middle of nowhere. Dad is caring and kind, and very much in love with Mum, who has just given birth. However, an accidental glimpse of a disturbing and well-hidden family secret brings Tom face-to-face with shock, denial, and--ultimately--rage. What mystery could be so appalling that it threatens to bring everyone in the family to their knees?