To begin, Mario strolls in from the bottom left corner into the stage. He must grab one of the vines just above to reach the ladders on the left side of the stage, or grab onto the tails of the Monkikki, which function as vines. After climbing three ladders, Mario will reach three Monkikki and a switch. Pulling the switch raises the wall enclosing the Monkikki, allowing Mario to grab the tail of one and ride across to the platform on the other side, where another switch is nearby.
Mario must now pull this switch to create a temporary platform filling in the gab above, waiting for one of the Monkikki to pass onto it, then releasing the lever to drop it onto the lower platform. He must then grab the Monkikki's tail and ride across the spikes. As the switch also raises the wall blocking off the key, Mario may then head back down and head to the right side of the stage. He may then collect the key and bring it to the nearby Key Door, which he may then unlock to clear the level.
Pauline's lost items