Diabolique

Mia Baran is a devout Catholic schoolteacher at a boys' school outside Pittsburgh where her husband, Guy, is schoolmaster. Guy is abusive to the weak Mia, a former nun who suffers from cardiomyopathy; his mistress, Nicole Horner, a fellow teacher at the school, is protective of Mia. When both women grow tired of his abuses, they collaborate to murder him in an apartment owned by a family friend of Nicole's. The women lure him there, and Mia drugs him before they successfully drown him in a bathtub. They wrap his body in a shower curtain and place it in a wicker box.