Let me structure the story. Start with the crew celebrating their victory over Stagnetti, but he's still alive. He's recuperating on the Spanish Main, vowing revenge. They have a goal, perhaps to find a powerful artifact to defeat the main crew. The main crew discovers a prophecy or a new threat, tracks down clues, faces challenges from Stagnetti's crew, leading to a climactic battle where Stagnetti's motives are revealed—maybe he was wronged in the past. In the end, perhaps a showdown where one of them is defeated, but maybe a twist ending.