The full story
Ulysses Bloodstone, patriarch of a family of monster hunters, is dead. His widow Verussa summons five hunters to Bloodstone Manor for a ritual hunt: whoever kills the creature loose in the grounds' maze inherits the Bloodstone, a relic that gives its bearer power over monsters. Jack Russell is one of the five. Ulysses's estranged daughter Elsa, who walked away from the family trade years ago, turns up to compete as well, to Verussa's open contempt.
The quarry has the Bloodstone fixed to its body. In the maze, Jack finds out who it is: Ted, the swamp creature known as Man-Thing, and an old friend of his. Jack came to rescue him, not hunt him. He strikes a deal with Elsa: he frees Ted, and she takes the Bloodstone. Ted kills one of the other hunters, Jack blows open the maze's outer wall, and Elsa pulls the stone free so Ted can escape into the forest.
The Bloodstone reacts to Jack's touch and gives him away: he's a monster too. Verussa captures them both and uses the stone to force Jack's transformation, meaning for him to kill Elsa. Instead, the werewolf breaks loose and tears through the guards. Verussa brings him down with the Bloodstone, but Elsa gets free, kills the last two hunters, and stops her stepmother from killing him. When Elsa reaches the werewolf, he lunges, then recognizes her and spares her.
Verussa goes for Elsa with a gun, and Ted arrives and burns her to death with a touch. By morning Jack is human again and Ted has found him. Elsa is left the head of the house, holding the Bloodstone, and the picture turns to color.