The Mystery Duck's Story is the fourth story in Where's My Water?. The Mystery Duck's Story is an optional In-App Purchase puts a magical twist on Swampy's Story. The regular Swampy Ducks are replaced with the teleporting and levitating Mystery Duck, or the water consuming Mega Duck, or a crew of ducklings. If the player doesn't collect the duck(s) on a level, S/he can not go onto the next. The pack cost USD 1.99.
The player can try the first five levels of this pack for free.
- The hidden Swampy level 'Planetarium' can be found in the Mystery Duck's Chapter but is called 'Mysterious Planets'.