The group ends up at an odd-looking mansion where they stop to ask directions, though it appears to be deserted. Misty leans against a wall and falls through it. Brock knocks on the wall and it is revealed to be a secret door, in which they quickly locate Misty. Suddenly, the same Venonat that was spying on them before appears. It hops away, so they decide to follow it. However, Ash runs into a small series of mishaps, such as being electrocuted by a Voltorb, colliding into an invisible wall, nearly falling off a ledge because of a wall trap and being pinned to another wall by several throwing stars. Then, a girl, who identifies herself as a ninja warrior Aya, jumps from the ceiling. Though Ash and Misty criticize Aya’s dangerous traps, Brock is smitten and compliments Aya’s outfit. However, she slaps his hand away and pushes him to the ground before claiming that she will not let the group go until she and Ash have a battle; he accepts the one-on-one match.
(Source: Bulbapedia)
