Episode 156 - Quest for the Pirate Lord's Riches! Luffy's Resolve

Episode 156
The Search for the Pirate King’s Treasure! Luffy’s Determination
Japanese: 海賊王の財宝を求めて！ルフィの決意
Kaizoku-Ō no Zaihō o Motomete! Rufi no Ketsui

The Straw Hat Pirates continue to search for the mythical island, but they are ambushed by a group of mercenaries who are working for a mysterious and powerful enemy. The crew must fight to protect their ship and the treasure maps they have gathered, while also trying to uncover the identity of their new adversary.