Poptropica Screen How Do You Get Back To The Robot Dragon On Poptropica Astro Knights?

How do you get back to the robot dragon on Poptropica Astro Knights? - poptropica screen

I played and laid it on the computer at the time my brother on the screen with the robot dragon volcano left on the planet. Now I can not go back into the room to fight the fire-breathing dragon robot because the horse is gone. Who knows how to go back there?