Engaged to a Psycho (2018)

Wealthy Karl gets engaged to rising online delivery delicatessen manager Deanna, buys her dream home and takes her to his rich family's ancestral country estate. His mother Ivy and adopted sister Ruby clearly hide mixed feelings, preferring a Danvers heirloom to her mother's wedding ring which disappears conveniently, as confirmed by the wedding planner, Karl's ex Sienna. The latter is only one of several staff and estate-associated people dying in suspicious circumstances, including the cook Sebastian and gardener Jimmy. Nothing stops the wedding preparations, Deanna's sister can't talk her over despite improbable 'accidents' and dark family secrets they find out, but a killer lurks.