Though a local researcher is widely regarded as a kook, captivated by his tales of a massive underground labyrinth dug by Trapinch, wherein these Pokémon secretly gather to evolve all at once into Vibrava, Ash and friends decide to give the man the benefit of the doubt. Together they descend into the labyrinth, following a tracer planted on one of the Trapinch, unwittingly leading Team Rocket as well to the Trapinch’s inner sanctum. These would-be villains botch yet another attack, but in the process manage to knock Ash and the ranger traveling with them down to a deeper level of the labyrinth. Fortunately, the tagged Trapinch is still by their side, but to escape, Ash and his new companion must traverse paths never walked by humans before.
S8 | Episode 10