The Submarine Explorer 1 sinks on autopilot while inside Blaise demands to know who Ruby is. Blaise's Slugma spits fire at Mumu, who counters, and Blaise orders Slugma to cover the floor in magma, so that the temperature skyrockets. As the heat builds, Ruby's vision distorts, and he tries to snap himself out of it, to no avail.
Blaise tells Ruby the story of the 'Little Matchstick Girl', a penniless little girl who sells matchsticks. When she lights one of her matches to try to keep away the winter cold, an illusion appears before her, and Blaise explains that he can do the same thing—use heat to create illusions in his victims' minds. As a demonstration, a formless monster appears and attacks Ruby, and Blaise brags to the shaken boy that he is known as the "Shadow of Fire."
Outside, Captain Stern, Dock, and the Pokémon Fan Club Chairman search for a way to bring the submarine back to the surface. Stern wonders why Team Magma is after the submarine in the first place. The Pokémon Fan Club Chairman suggests that since the strange people want the submarine and it can't work without its special component, they should stop the component from being produced. Stern says it's too late, the Devon Corporation has already finished it, and it was stolen from Mr. Stone a few days ago, who is still in the hospital. Since Mr. Stone alone knew about the component, no one in the world knows where it is now that it's been stolen, except the thieves themselves.
Inside the submarine, Ruby struggles in the sweltering heat. A vision appears before him of his father, Norman, looking cold and stern, and a younger Ruby runs up to him, begging his father to teach him about Pokémon battles. Norman does not respond, and the illusion shatters, bringing a gasping Ruby back to reality. Blaise taunts him, asking whether the illusion he saw caused him pain, and claims his illusions force people to relive their worst memories. Ruby, in turn, defiantly says that it's Blaise's unlucky day. He might have seen his worst memory, but that same memory is what inspires him to stand up again. He calls to a weakened Mumu to use Earthquake.
The force of the attack rocks the submarine, and Blaise angrily asks whether Ruby's trying to drown them both, but Ruby just orders another Earthquake before recalling Mumu and crawling over to the side of the cabin. He tells Blaise that he was able to tell Blaise's Slugma's Nature simply by observation—that any Pokémon can be understood if you pay attention to its behavior and unique characteristics, and that he learned that from his father. Ruby then activates the escape pod he has managed to crawl into and shoots toward the surface, leaving Blaise behind in the sub.
With Ruby gone, Blaise steals the submarine, sailing it out into the ocean, and calls Maxie to tell him of the mission's success. He also explains that they need a special component from the Devon Corporation in order to make the submarine fully functional, and that once they have it, they'll be able to reach the Seafloor Cavern.