It all started with a gruff man coming into a bar that Luffy and Shanks were in. When the Man broke Shanks' bottle of drink Luffy wanted him to fight him. Shanks, however, didnt and just laughed it off. Well, Luffy didnt take this too well, he thought that a pirate was supposed to fight people like that. This got him mad and he unknowingly ate a cursed fruit. Later Luffy found the same man that spilled Shanks' drink and tried to make him apologize. but this just resulted in Luffy getting beat up. Thankfully Shanks came to his resque. But the man got away and threw Luffy in the water where he was attacked by a sea monster. but once again Shanks saved him, this time at the cost of his leg.