In Henry Kuttner's 'The Salem Horror,' a writer named Carson moves into an old house in Salem, formerly owned by the executed witch Abigail Prinn. He discovers a hidden 'Witch Room' in the basement, designed to revive Prinn's spirit. Carson's writing is influenced by dreams and he uncovers Prinn's plot to summon a dark entity. An occultist, Michael Leigh, intervenes, and together they thwart Prinn's plan, sending her and the entity back to their realm, though a chilling memento remains.