Toadette is on a fort that can be rotated around. There are green and orange sides. You will start on the green side. Homing Bullet Bills will fire at you. Walk around to the other side of the green side. Cross to the orange side and hit the POW Block for the first gem. Walk back towards the center and rotate the gear to rotate the orange side of the fort. Rotate it so you get the flat area with two Piranha Plants and a Bill Blaster. Go past the Bill Blaster and you'll find another gear that rotates the green side. Rotate the gear until you see a gem and two Bill Blasters. Walk past the Bill Blasters for the second gem. Walk back to the green gear and rotate it so you can reach both gears with it. Rotate the orange gear so that you can see the Star, but can't reach it. Walk to the other side, with the red Bill Blaster and pick the plant for the third gem. Go back to the orange gear and rotate it so that the three Piranha Plants and the Star are facing up and, but you can't walk from the orange gear to the orange side. Walk on the green side, then go to the orange side to get the Star.
Special Challenge: Do not take damage.