The Darkening Hour — Penny Hancock

Mona, a migrant domestic worker is employed by London housewife, Theodora. At first Theodora only asks Mona to clean and cook for her, but as unwanted pressures begin to take their toll, she deflects these onto Mona. Slowly, imperceptibly, Theodora's demands increase until she is treating Mona as nothing better than a slave. Mona is going to have to take extreme measures of her own to escape the control of her increasingly abusive employer. So when a murder is committed, who is to blame?