Brimstone and Treacle (1982)

Synopsis
The arrival of a mysterious stranger disrupts the lives of the members of a British family in this dark, psychological thriller. The stranger is one Martin Taylor (Sting), a dangerous charmer who ingratiates himself with the Bateses, a dignified, older couple (Denholm Elliott and Joan Plowright). The couple becomes especially fond of Martin after he demonstrates a strong, caring rapport with their daughter, a disabled invalid. It is only when he has become a part of the household, unofficially serving as the daughter's caretaker, that Martin's true, potentially demonic nature begins to show itself. Based on a script by Dennis Potter, the creator of the brilliant British television miniseries Pennies from Heaven and The Singing Detective, the film layers its already charged situation with hints of the supernatural, aspiring to be both disturbing family drama and provocatively ambiguous morality play. Some moments of MTV-like stylization threaten to diminish the mood of slow suspense and unhealthy obsession, but Potter's distinctly warped sensibility and the solid performances generally carry the film over its rough patches. ~ Judd Blaise, All Movie Guide