Dark Shadows Pb Lib Novel Volume 21 Haunted Cave

Harriet Turnbridge asks Barnabas Collins for help after her husband, her brother-in-law, and father-in-law are found dead, their throats savagely ripped open. The police insist the killer is a mad beast. Harriet thinks that the phantom recently seen at Collinwood is responsible. Barnabas suspects that Quentin Collins, disguised as a wealthy hippie, is guilty. Where will they find the murderer? In the nightmare world of Harriet's dreams? In the haunted cave beneath the Collins' family cemetery? Or in another century - when witchcraft and demonology threatened Collinwood?