An ancient stone path leads to an ominous jagged mountain. It is the home of a certain dragon-like Pokémon, one of the two that the Pokémon Trainer aims to capture. To find this beast, they must venture in the dangerous ruins within the mountain. But first, they must fight their way across Subspace Army-riddled path and make it to the mountain safely.
The road to the ruins is a treacherous one. Not long after you start off, there will be a lot of electric Jyks, pits and spiky floors. Maneuver around them carefully to avoid taking too much damage. Go right until you come across a long floating platform. Here, you will be forced to battle some Puppits and Shellpods to advance. After the fight, the path drops into a deep valley.
There are two paths you can take to continue. You can try and clear the slope of spikes to your right to skip a small part of the stage or you can break the stone blocks to open up a tunnel in the slope. If you choose to go the lower path, you can find some item blocks within. Take the elevator at the end of the tunnel to return to the surface. No matter which route you take, you will soon face some Gamygas around the elevator. These tall enemies block your path forward and fire lasers at you which do quite a bit of knockback. You can destroy its bases one by one to reach the mask at the top or attack the mask to defeat the entire creature at once.
After the Gamygas are several pits. Most of them are bottomless, but the third one you come across has a secret door inside it. Fall into it and enter the door to reach a room filled with breakable blocks. Break some of them to let you reach the gaps containing trophies and stickers. Once you're done, go through the door to return outside. Jump up the multiple platforms to reach the surface again.
The path ends at a cliff. To make it to the other side, you must jump on the floating platforms to get across. As the arrows indicate, standing on them for too long will cause them to fall, so leap from platform to platform quickly. Don't forget to dodge the Jyks and get the item inside the gold item block, which is fortunately located on a non-falling platform. Go into the large cave entrance to reach the next area.
Move right into a large room above a lava pit. Watch your footing as you jump across the floating platforms, and avoid the fireballs that shoot out from the pool below. After the pit is some fire jets and some Fire Primids. The fire jets activate periodically, but you can turn them off temporarily by attacking the buttons in the tunnel. There are more similar buttons ahead, so keep them pressed so that you don't have to deal with the fire jets.
After a small stone staircase lined with fire jets, you will reach a vertical shaft. While there are arrows pointing below, your goal is actually to go up. Jump up to the ledge at the right end of the shaft, then jump up to the left to reach an alcove containing a gold item box. Beware of the Armights and the fire jet that guard this box. Drop down the shaft once you've taken its contents.
At the very bottom, you can go left to find a blue item box, but you must go right to progress. You will be locked in battle in a large room with a group of enemies, including the first appearance of Glires. These fiery relatives of Glunders attack the same way, but instead of a multi-hit electric strike, they only launch a single-hit flame attack.
Continue right into the next room, where you will face some Nagagogs. Use the force balls to help you wear their health down. The room to the right is another forced battle, with the additional threat of falling to your death since it takes place on a floating platform. Go right into a huge room and on to a floating platform, which will slowly rise and trigger yet another forced fight.
After the series of battles, take the elevator to the surface. Go left to find a blue item box, then go right to reach the door to the next section. Once you go through the door, simply run along the path to the right to trigger a cutscene.
Arriving at the entrance to the ruins, Lucas and the Pokémon Trainer are stopped by Wario, who aims to make up for his stolen trophies. Recognizing the foe that turned Ness into a trophy back at the zoo, Lucas prepares to avenge his friend with some help from the Pokémon Trainer.
The battle with Wario will be a bit annoying due to the layout of the stage. The two pillars at both sides of the stage make it difficult to knock Wario out horizontally. You must either attempt to KO him vertically or try to lure him to the area behind the pillars, where you can easily knock him into the blastlines. As you should have some extra stocks while Wario only has one, the fight shouldn't drag on for too long before you finish him.
Having turned Wario into a trophy, Lucas and the Pokémon Trainer celebrates victoriously. However, Lucas's joy quickly turns to disappointment, as Ness's trophy is nowhere to be seen. The Pokémon Trainer cheers him up, and both boys peer into the imposing entrance of the ancient ruins.
Meanwhile, inside an old castle, King Dedede is cleaning up his trio of trophies. He takes out some badges and puts one on Ness and Luigi. He quickly notices that he lacks a badge for the princess, and reluctantly puts the badge he was wearing on himself on the princess. Suddenly, the roof of the castle collapses, knocking King Dedede out cold, as Bowser's forces invade his hideout. Among the pile of rubble, Bowser spots the trophy of a princess sticking out from the rubble...