Chapter 668

Chapter 668 is called "Pirate Alliance".

Cover Page
From the Decks of the World Vol. 48 (Final) - "Whitebeard and Ace's Graves".

Short Summary
Luffy accepts Law's offer of an alliance to defeat one of the Yonko, despite the initial misgivings of the remaining Straw Hats. Law returns Franky and Chopper to their original bodies, leaving Nami to go into Sanji's body. The group establish their current objectives: to discover a cure for the children, to find the samurai, and to kidnap Caesar Clown. The G-5 Marines battle a unit of centaurs. In the Burning Lands, another group of centaurs release a gigantic Slime creature on Caesar's orders, which quickly annihilates them all.

Chapter Notes

 * Edward Newgate and Portgas D. Ace's graves are seen for the first time after the time-skip. The mini-series "From the Decks of the World" ends.
 * An alliance is formed between the Straw Hat Pirates and the Heart Pirates.
 * Law, Zoro, and Sanji are confirmed to posess Haki.
 * Chopper and Franky return to their original bodies, and Nami is placed in Sanji's body.
 * Caesers minions engage the G-5 Marines.
 * Law and Chopper head off to find medicine for the kids.
 * Caesar Clown has unleashed a creature called "Slime".