Hallowmas is the story of a melancholy young Benedictine monk who, after several years at a Midwestern Abbey and University, suddenly finds himself facing some dark and disturbing "ghosts" from his past.   Triggered by icons of holy virgins, red vigil candles, Halloween jack-o'-lanterns, and the smell of baking bread (among other things), Brother Thomas lapses uncontrollably into a series of flashbacks which slowly unravel the string of ironic catastrophes which shaped his present state.

After discovering the corpse of an old Ojibway who appears to have hanged himself from the belfry of an abandoned Indian Chapel (actually lynched inconsequentially by a cult of itinerant cattle mutilators), Brother Thomas spirals into a compulsive self-defeating cycle of isolationism, blasphemy, sexual obsession, and a phobia of being touched by other men, wrought by the abusive circumstances surrounding his own mother's tragic "suicide" when he was a child.