Captain Toad finds himself on a small network of beep blocks. Walk forward onto the pink beep blocks, then to the safe blocks. Pick a turnip and toss it at the first gem, which can't be reached when the blue blocks appear. Go to the right and you'll find a tunnel under a safe block. Go through it when the blue blocks appear, then go around the corner and you'll find another tunnel with the second gem. You can reach it when the pink blocks appear. Backtrack to the turnips, then head left to where there are ladders on the pink blocks. Climb the ladders, which will still be there when the blue blocks appear. You can hang onto them while you wait for the pink blocks to appear. At the top, drop down to the blue blocks, then the safe block in front of them. Dodge the flames of the Fire Bro. When the blue blocks appear again, run down the long set of blue blocks and hang on the ladder. At the top, there's a safe block with a Mushroom. Climb up the ladder on the pink blocks and pick a turnip from the safe block. When the blue blocks appear, stand on the nearest one and hit the Fire Bro with it. Carefully time your drop from the blue block to the pink blocks below, then pick the plant where the Fire Bro was for the third gem. When the blue blocks appear, drop down and go to the Star.
Special Challenge: Do not take damage.