For this achievement, you must find and complete all 5 stories before finishing the game. Each story has an achievement tied to it so it's easy to keep track of which ones you've done. The achievements you're looking for are:
- Sap (1:15)
- Fangs (15:58)
- Behind the Veil (23:52)
- The Wish (27:12)
- The Curse of the Sea-Thing (47:48)
The achievement will unlock when the credits start rolling.