Wet Dry Valley is the 12th stage in Super Mario: The Power Star Journey. Directly when Mario enter the 2nd overworld, enter the star locked building on your left. This door requires 50 stars to unlock, which is the highest amount in the game besides the door to the final boss. The reason for this is this small area not only contains the path leading to this course, but a secret warp hidden on the a portion of the wall where you entered the room. This warp will lead players to the 4th and final overworld containing Course 15 and the Final Bowser fight.