you should go to the most down which is also going a little bit to the right passageway.
the one with the red walls which are looking like the inside of a body ...
the one with the green zombie frog piple and the green gas ...
anyway , there is a coin , shield , whatever thing in there - bind it - then bring it to the throne
room , put it in the middle thrones back , and sit on the throne .
it will open a passageway to the right which leads to ... well , youll find that out
yourself (wont u?) ...
hope that helped ...
