Following the death of Andrew Marr, an aging inmate at the St Columba’s asylum, Edward Foster ( Robert Hardy ) travels to the small town of Marr’s Halt and claims ownership of the Marr’s Grove estate in the will. Sarah Mandeville ( Joan ), sister of the town doctor, volunteers to be his housekeeper so as to inveigle herself into Foster’s trust, later becoming his lover. Unknown to Foster, Sarah and her brother Ian ( Christopher Lee ) are seeking to obtain the £210,000 that is supposed to have been hidden somewhere in the house. They contrive to fake a series of hauntings to make Foster doubt his sanity. As he begins to ‘see’ things around the house, Foster becomes overrun by memories of what happened the past, of how Marr was planning to leave his wife ( Jean Marsh ) with the babysitter Alta ( Jane Birkin ) only to befall a terrible fate.