Review,
Picking up from 549, Luffy and gang continue to advance to Marine Headquarters. Marine Headquarters is also being heavily guarded by marine ships, marines from all over the world, Royal Shichibukai, the three high admirals Kizaru, Akainu, and Aokiji. Then later at Marinford, Sengoku announces the reason why Ace is being executed. Turns out his mother is Portugas D. Rouge who gave a son to the infamous pirate king Gold Roger. Dang dang dang!!!
Link to One Piece 550 : http://www.onemanga.com/One_Piece/550/