The Mutiny system is a questlike system for more advanced players.
This system is a solo system. You cannot do it in groups.
To start his system you will need to obtain A Pirate's Treasure Map. You can obtain this in a Recovered Treasure Chest from the Swamp Digging system.
The Pirate's Letter will give you information on what you need to do to finish this quest.
This wiki will have more updated at a later date.