Chapter 671

Chapter 671 is called "The Gas-Gas Fruit".

Cover Page
"Chopper Pulling a Pumpkin Carriage While Nami and Some Mice Enjoy Themselves." -A request by Akemi Isaka (井坂あけみ) in Ibaraki Prefecture.

Short Summary
Slime continues to spit pieces of itself across the lake, poisoning the water in the process. Despite this, Sanji dives in and searches for the samurai's torso. Law asks Monet to accompany him through the laboratory, saying he has need of her "ability". Caesar Clown slips out of Luffy's hold, and demonstrates the combat abilities of his Devil Fruit as the two fight each other. Although Luffy appears unharmed after all of Caesar's poisonous and explosive attacks, he spontaneously collapses and Caesar laughs in triumph. Shortly after, Law suddenly falls down injured in the laboratory, before being confronted by a mysterious figure he recognizes.

Chapter Notes

 * Sanji jumps into the lake to search for Kinemon's torso.
 * Luffy fights Caesar Clown.
 * Robin confirms that while a Busoushoku Haki user can touch a Logia's real body, the power cannot seal away Devil Fruit abilities the way that the sea or Seastone can.
 * Caesar shows some of his attacks using his Devil Fruit.
 * Caesar's poison gas attacks doesn't work on Luffy who is immune to poison after his fight with Magellan during the Impel Down Arc.
 * Law leaves Chopper inside the research facility.
 * Law asks for Monet's assistance and heads off to the research facility with her.
 * Monet is hinted to have an "ability."
 * Luffy collapses during his fight with Caesar.
 * Law collapses inside the research facility, as an unknown figure approaches him.