The Underground Tunnel is a location beneath Cavi Cape and located west of the Toad Town Tunnels. Bowser is catapulted here by a group of Bob-ombs shortly after Fawful abducts Peach by using a laser-like machine to remove her from his body. Only two types of enemies appear here. This area seems to be an abandoned underground railroad. After navigating the tunnels, Bowser meets up with the Monty Bros. One of the four exclaim that they are trying to make a tunnel that will connect them to Toad Town. They use a huge machine to get the job done. A disgrunted Bowser relunctantly helps them achieve their goal. Mario and Luigi have to go to the Leg Outpost to give him power though. Bowser has to achieve this before the battery dies in ninety seconds. Bowser's power overcomes the challenge and the machine is totaled. Bowser heads in the next room to the Toad Town Caves.