On the way to the Battle Pike, Ash and friends stumble across a ninja school. However, there have been thefts around the school lately and they are told to be alert. On one of their tasks, which is to find the teacher's Kecleon, Ash and another Ninja stumble across a Bonsly. Bonsly is quickly blamed for all of the recent thefts at the school but Brock quickly proves them wrong. Soon after, the real thieves, which is none-other than Team Rocket, show up to steal all of the Pokémon at the Ninja School! (thetvdb.com)