Return of the Djinn is a Ninjago: Masters of Spinjitzu book that was released on June 28, 2016.[1] It records the events happening in "Infamous."
Official Description[]
It's a peaceful time on Ninjago Island. The ninja have defeated the Preeminent and destroyed the Cursed Realm. Now Cole, Jay, Kai, Zane, Lloyd, and Nya are famous throughout the land, and they're enjoying a little time off.
Enter Nadakhan the djinn, a famous pirate and genie. He's back in Ninjago, and he's got big plans for the Destiny's Bounty, his old ship -- and for the ninja. Can they stop him before he tears their group apart for good?