When Lena, a young Polish immigrant working as an office cleaner at Heathrow Airport, misses her last bus home, she accepts an offer of help from friendly co-worker Birdie, who lives nearby with her 'adoptive' parents. Knocked unconscious after arriving at the house, Lena soon finds herself imprisoned in a suburban House of Horrors, a living nightmare of abuse, torture and murder. Designated a 'Mummy's Girl', Lena's only options appear to be to become part of the family - and join Mum and Dad in their insanity - or die.