Dragon Masters 3: Secret of the Water Dragon

Why does someone want to steal the Dragon Stone?
Bo tried to steal the dragon stone because he wanted to give the dragon stone to the Emperor Song because Emperor Song was holding Bo's parents in prison and he wanted to free them.

Describe the Raven Guards.  What are they like? 
The raven guards wear black masks. They also wear black clothes.  They have swords and are spies.  They look like ninjas.

--Grace