Crisis from the Underground Up! (激走！バトルサブウェイ！！（前編） Flat-out Run! Battle Subway!! (Part One)) is the 49th episode of Pokémon: Black & White.
Ash and co. finally arrive at Nimbasa City, where Ash hopes to get his fourth badge. Cilan is happy as a kid in a candy store to be on a subway as he's a Metro Connoisseur, and as they were riding, they suddenly stop and saw a mysterious ghost train passing through. They meet Ingo and Emmet, the Subway Bosses of the Battle Subway who are investigating the cause of this disturbance. However, as Ash and co. got to the Pokémon Center, all communications has been cut offline, and the Driftveil Drawbridge is offline too. Plus, Meowth's plan had come to fruition, but what is it? He's going to betray Ash and co. by going back to Team Rocket as he steals every Pokémon in the Pokémon Center including Pikachu and Axew in their ghost train.
The heroes has arrived to Nimbasa City. Cilan checks that many trainers come to participate in many battles, which is why Nimbasa City has many facilities around. Meowth tells them he needs to go to the Pokémon Center, for he is exhausted. Ash wants to go to the Gym right away, but Iris hears Pikachu and Ash's stomachs grumbling, thinking they should also get a meal. Cilan leads them to the Subway, for this is the only means of transport in Nimbasa City. Iris thinks he is a little kid to love trains, but Cilan replies he is a Metro Connoisseur. Cilan admires the trains, but Ash thinks it is an ordinary cart. Cilan explains that is a double train, the first mass-produced train to contain small number of machine parts, for it can travel faster and is less expensive to manufacture. As Cilan continues to ramble, Meowth pulls him away, for they all are hungry.
Inside a train, Iris tells Cilan he is embarrassing them, for he is starting at a window. Cilan points out there is nobody controlling the train, for it is automatized, controlled by the main computer. Suddenly, the train stops, as the emergency system has been activated. Iris notices a train passing by and remarks he has not seen such a model, while the others tell it is a ghost train. Iris and Ash spot two lights in the distance, which Cilan recognizes as Subway Bosses. Cilan clarifies to Ash and Iris they are responsible for running the Nimbasa Underground. Ingo and Emmet arrive and fix the system, making the train to be powered again. Ingo and Emmet are glad to see Cilan again, being an subway lover. They explain that some days ago this haunted train appeared and goes through the subway. However, they cannot stop it, plus it vanishes mysteriously. Cilan is enraged someone would do that, though Meowth pulls him away.
When they come to the Pokémon Center, the heroes admire its size. Nurse Joy tells them the center is large, for there are quite many trainers that battle around Nimbasa City. Meowth heard of the relaxation chambers and would like to go there to rest. He asks the twerps to send their Pokémon to enjoy the relaxation, which they do. As Ash, Iris and Cilan go to eat, Meowth forgot something and goes to phone someone. Meowth calls Dr. Zager, telling him to initiate the operation and goes back to go to the relaxation room. Ash remembers he needs to make a call. Meowth comes back and explains to Axew and Pikachu Audino or Nurse Joy need to touch the pad to unlock the door, for that is a security system. Ash calls Prof. Oak and tells him he is in Nimbasa City. Oak is pleased to hear that, but Dr. Zager disrupts the communications, causing Ash to lose the link with Oak. Meowth tells Audino to take a break, while he has an evil grin on his face, for Pikachu and Axew are asleep. Dr. Zager manipulates the drawbridge.
While Ash tells Iris and Axew his call with Oak got cut off, Meowth opens a vent and throws every Poké Ball he can find, including Axew and Pikachu. The Pokémon go through the vent, into the train, controlled by Jessie and James, knowing Officer Jenny is busy with the drawbridge problem. The heroes arrive and Joy warns them the drawbridge has been manipulated. Cilan sees it is part of a plot to steal Pokémon. When they enter the relaxation room, they see it empty. Ash, Iris and Cilan find an alternate route by crawling their way through the vent, while Meowth meets with Jessie and James. Dr. Zager stops all the trains, while Ingo and Emmet are terrified someone hacked into the system. The heroes encounter Team Rocket and the haunted train. The truth is revealed; Meowth was lying about being fired from Team Rocket and was traveling with the twerps to earn their trust, so Team Rocket could steal their Pokémon. Jessie sends Woobat, who uses Air Slash., to distract them as Team Rocket rides the train.
Ingo and Emmet see this is Team Rocket's plot. They tell even with the trains stopped, Team Rocket can still continue through the connecting lines to get away. They know Team Rocket cannot go directly, though they cannot see them on the map. On the map, the Bosses see they have to go through a central point, allowing them to set an ambush. The heroes want to take a cart to rescue the Pokémon, which the Bosses will allow. They get aboard the cart and start the engine, while the Bosses try to fix the system. After a while, the heroes reach the point and encounter the train. Ash jumps, but the train collapses and explodes in a smoke, causing the cart to crash. Ingo and Emmet managed to fix the system, so Cilan reports they crashed and Team Rocket used a decoy trains. The Team Rocket train passes by, though the Bosses have them locked. However, more dots appear on the map, so they see Team Rocket is using more decoy trains, but cannot determine which is the correct one.
- "But I want to look at the pretty trains some more!" - Cilan
- "Who's That Pokémon?:" Woobat
- When this episode first aired, an opening promoting the one hour special event was shown as a cold open, followed by the opening theme. The title card was not played after the opening, and the actual cold open scene of this episode was shown after the opening. Only where the opening theme is shown during the normal standalone version of this episode is when the title card is played in the original airing. Also, the ending theme for this episode, the Professor Oak's Pokémon Live Caster segment, and the next episode's preview were skipped, as original airings treat the preview as a promotional clip, unlike other versions including reruns and DVD where it is treated as an episode segment, as Battle for the Underground! was airing next in the special, and one hour specials regularly remove the episode's side segment from the first episode airing as well.
- The fading of the screen to white to show the opening song was also cut in the original airing, showing the title card segment just after the cold open to this episode. It is restored in the normal standalone version of this episode and international dubs.
- This marks the first time Iris and Cilan heard their (alternate) Sinnoh motto.
- Meowth leaves Ash and his companions, revealing that his "turning over a new leaf" was merely a plot to infiltrate the Pokémon Center.
- The official English Pokémon website listed this episode under the tentative title "To Catch a Ghost Train!" when it was first posted. This was corrected to the finalized one "Crisis From the Underground Up!" months later.
- This episode was shown in the UK before it aired in the U.S. not only once but twice.
- This marks the first time since the start of the Diamond & Pearl series to mention Tracey.
- Strangely Ash and co. crawl along on their bellies while traversing the vent even though the vent is high enough to accommodate crawling on their hands and knees (which would be a faster way to move).
- Meowth pulled Cilan in a fashion Brock was pulled by Misty, May and Croagunk.
- When Ingo and Emmet pointed their fingers up in the original, Ingo said, "We need to investigate further". However, in the dub, Ingo said "Always follow safe triangles. Point your finger to signal OKAY!".