Vash and the boy are hiding in the ventillation shaft of the steamer. The boy takes out some plans of the steamer's blueprints (that he copied from his father when he was younger) and shows Vash. The boy also tells Vash that B.L.G. wishes to drive the steamer into a canyon to break it in half. Through flashbacks, we learn that the boy, named Kaite, had a very loving father who dedicated his entire life to the development of the steamer. Kaite's father always wanted Kaite to devote his life to something grand and Kaite sheds a few tears remembering this.
Vash and Kaite leave the shaft and take out a few gang members. Vash takes all the members' weapons, lots of machine guns. Vash and Kaite then go into a room and use one of the fallen gang member's communication device to radio in to Brilliant (posing as the gang member), telling him that Vash is superhuman and that he's in a specific area of the steamer.
Vash then gets ready to leave, giving Kaite a pen that has very high-tech communication features (so Kaite can guide him). Kaite is absolutely stunned, knowing the pen to be made from a technology lost long ago. Vash doesn't offer an explanation as to how he got it and just leaves.
A few steps out of the room, Vash sees the gang members he shot earlier. He gets distressed, realizing that they might die (Vash made a promise to some yet-unknown woman long ago never to kill). Vash then works hard, trying to seal their wounds.
Vash begins to charge through the steamer, using Kaite's directions. He takes out a good number of gang members. Finally, Brilliant figures out that Kaite is navigating Vash and sets up an ambush - the ambush is successful and Vash is held at gunpoint by a large number of armed men, including Brilliant himself. Kaite is also captured.
Brilliant is about to shoot Vash when one of his own members turns and points a gun to his throat. Brilliant is confused until the gang member reveals herself as Meryl. Another gang member then reveals herself to be Milly. They call Vash by name and everyone in the room gasps.
The train begins to stutter - there isn't much time before it hits the canyon. Vash and Brilliant draw their guns, in preparation to duel. Brilliant agrees to stop the train if Vash wins.
So Vash and Brilliant duel but it's a very confusing one. Vash hits Brilliant a few times (though causing minimal damage) and Brilliant misses (though Vash was already hurt before the duel and is wounded on the floor anyway). Brilliant refuses to shoot Vash (though he has an easy chance now) because it would be dishonorable and he wants to win fame the hard way.
Everyone applauds that Vash won the duel and the captain orders the steamer to stop. The brakes won't work though.
Kaite tries to help the crew of the steamer stop it but they won't accept his help (recognizing him as a member of the B.L.G.). Kaite then, on his own, hits the emergency brakes and stops the steamer. But it's too late.
Or is it?
At the last second, Brilliant Dynamites Neon steers the steamer to a stop. He paid off his debt to Vash (from the agreed-upon bet of the duel). He then tells Vash that the next time they meet, he's going to kill him.
The next day, Kaite and Vash sit atop the steamer (which is right on the edge of a great cliff, leading into the canyon). Kaite begins to sing a song and Vash gets emotional because the song Kaite's singing is the same one the mysterious woman of his past used to love as well.
The episode ends humorously when Kaite thinks Vash is making fun of him by crying so much at the song.
