Where is the fouth medallion in Port Royal chapter 2?

Please Answer!

It's either in The Ship Wreck place, or the Isla de Muerta. The Nobody in the Isla de muerta is either in the caverns hiding ( You have to blow up the boxes) or in the second area from where you begin.

Or at Isla de Muerta, i just go to the last room (treasure room) and look through the dark and just fight the gambler, defeat it, and done, the final boss of POTC. GL!