On the hunt for an obstruction, Mario takes a trip through Discordia’s convoluted, labyrinthine water system. Why were things designed this way? Well, that’s a long story involving a disastrous lack of planning and infrastructural incompetence... But none of that really matters. Mario’s just the plumber.

Mario’s been getting a lot of calls about Spinies clogging people’s sinks lately. He follows the problem all the way to Discordia’s biggest water reservoir, which is chock full of the things! But how did they get here? Mario’s gonna have to take a deeper dive to get at the issue’s source.

Mario’s search for the Spiny source takes him to a vast cerulean facility. Spinies are being held in containment units as robotic Mechakoopas patrol the area, attacking any intruding plumber on sight. What kinds of experiments have been taking place here? Mario must destroy the lab and put an end to this obstructing atrocity.

The air of Munch-Munch Mansion is constantly being cooked by roiling lava, just how the Munchers like it. It’s long been thought that the Munchers built the mansion themselves, but Mario doubts their masonry capabilities. He has a hunch-hunch that the real architect of the manse is waiting somewhere further in...

An ambitious construction project aims to build all the way to the stars, but something’s gone wrong with its waste management facility and now it’s filling up with poisonous goop! Mario will have to climb above the muck before he can even begin to diagnose the issue.

Oh no! Wendy O. Koopa is trying to steal Warp Pipes from the waterworks! Mario must jump from ship to ship to ascend her armada and stop the kootie-pie's heist. But her navy is not going to make this a walk in the park, with Bullet Bills, Rocky Wrenches, and parachuting Goombas ready to ruin Mario's work day!