There are four steps to this achievement, all involving fights with Dolce the pirate. This is only available on your second play through.
- Pirate's Paper 1: Defeat Dolce on her pirate ship. It's impossible to miss this step because the story progresses through it.
- Pirate's Paper 2: Defeat Dolce in the Wah Lava Cave. In the "Middle 3" section there is a flower that has a red dragon in front of it. Kill him and examine the small X on the ground to trigger a fight.
- Pirate's Paper 3: Examine the six pillars in the catacombs under the church in Ritardando, then go talk to the employee who is sitting on some barrels in the wine cellar of the inn of Baroque. When prompted with a choice say Dolce's skin is looking saggy and she will appear.
- Treasure & achievement: Return to Woodblock Grove (the poisoned woods) and in the "South Center" section where you have to go left on a hard to see path there is a small device/sign. Input 3214 when prompted for the code and Dolce will appear for the final fight.