Captain Toad finds himself on a large, cube-like structure. There are Bullet Bills and Conkdors. Go around the corner and dodge the Bullet Bills by standing by the brick in front of the Star. Step on the P-Switch to rotate the cube and you'll land on the new floor. The plant between the Conkdors has many coins. Carefully walk around to the next P-Switch, which rotates the cube again. The P-Switch here is nearby, but leave it alone and walk to the right of the Bullet Bills for the first gem, which is behind a wall. Hit the P-Switch, then go towards the Conkdors. Pick a turnip and walk to the left of them. Toss the turnip at the second gem. There are two P-Switches here. The one farther from the Conkdors has a nearby plant with a pickax. Grab it and step on the P-Switch, then run to break the brick in front of the Star, then the brick in the opposite direction. Break one more brick around the corner so you can reach the third gem.
Special Challenge: Don't take any damage.