This game tries to reproduce a famous 1672 jailbreak of about 30 pirates from the supposedly impregnable fortress of Cartagena. Each player controls a group of pirates and tries to have all of them escape through the tortuous underground passage that connects the fortress to the port, where a sloop is waiting. As soon as a player has brought his pirates aboard, the sloop sails away and the game is over. In the original game the number of pirates for each player is 6, in the online version you can choose the number of pirates each player will use during the game in a range from 4 to 8.
You can read the rules by following this link.