While travelling through a cave catching Zubats, Rusty is captured in a net by Team Rocket. They tell him that he is on their territory.
At some point before Rusty's arrival in the cave, it was marked by Team Rocket as thier territory.
While in the cave, Rusty is confronted by two Team Rocket members, one a girl and one a guy. After they capture him in a net, they threaten him, but he instantly surrenders all of his Pokemon.