The gang encounters trouble while traveling on the subway.
When Arnold and his friends leave the movie theater — they had watched Killer Vegetables from Space — the sun has gone down already. The kids become worried because they should have been at home before sundown. Since the way is too long to walk, they missed the bus and don't have enough money for a cab, Arnold suggests to use the subway. Everyone is shocked. Gerald tries to put Arnold off the idea ("You know what they say about taking the subway after dark: Sun goes down, stay above ground.") — without success.
So the kids enter the subway station and take the Eastbound D Train. But just when they are leaving the station Arnold wonders if they are in the right train. Gerald checks the time table and concludes that they are actually in the wrong train — but that problem can be easily resolved with changing train a couple of times. After the kids have calmed down, they look around in the car: Apart from them there are a homeless person (sleeping well), a slim man with a corpulent woman, a psychologist with a female patient (suffering from claustrophobia) and a Blind Man with a seeing-eye dog.
Just as things seem to be going well, a rat bites through the subway's power supply cords on the pantograph and causes the train to stop and the electricity to go out. The driver tells the passengers that there was no danger but his voice sounds quite hysteric. So Helga suggests to walk to the next station but when she opens the door and sees many rats outside, she changes her mind. Grandma learns about the accident from the TV, so she strikes out to rescue the kids. Meanwhile the general mood of the passengers worsens and everybody begins to panic. When the blind man suddenly smells that Harold is secretly eating chocolate, everybody enrages even more. Then Arnold notices that the seeing-eye dog doesn't feel well. In fact, Killer appears to be a female dog after she gives birth to puppies.
Meanwhile Grandma has arrived and repairs the power supply cords, so that the train starts moving again. Now everybody is enlightened and they all are singing a song together.