The Rats go to their first mission to stop Davenport’s hi-tech, super fast train from speeding out of control and blowing up the town of Welkerville, where Izzy attends Welkerville University there. But when Leo sneaks along in a bag where the braking system was, the Rats discover he accidentally discarded it. They were supposed to install it to the train, and now they must improvise a way to stop the train before it crashes into a nearby town. They decide that Donald can give them the decelerator, but it falls in the wrong spot and Adam tries to pretend that he got the decelerator. Chase uses his bionics and calculates a plan when Leo gives him an idea by mentioning something that happened on a cartoon TV show. The plan goes into action and they successfully stop the train.
Meanwhile, Tasha is given her big break at the TV news station, when her boss asks her to cover the runaway train. She always misses it in some way and at the end,thanks to her cameraman Robert, she says the train miraculously stopped. She goes inside and tries to find the person who stopped the train, instead finding Leo, to her utter embarrassment.