Night Wolf (2010) on Netflix

Plot summary

Sarah Tyler comes back to her family's house in the English countryside after several years in Los Angeles. Her brothers and their friends are drinking in the barn, and her youngest brother Luke mentions their parents' fights over money and a rumor about their mother. Stephen says the stepfather believes a man her mother pays is her lover. The storm outside knocks out the power. Blood at the top of the staircase leads them to a body in her father's room, mauled by a wild animal. The group is cut off from the outside world, and something beast-like is hunting them through the house.