In New York City, four mutated turtles are taught ninja skills by a mutated rat.

The great detective Banana Fox is called back to duty to find a missing turtle. But the deeper he digs, the more he discovers, and it's worse than he thought! The Secret Sour Society is back, and they're mixing up a bunch of trouble. Can Banana Fox and his sidekick, Flashlight, put an end to the Secret Sour Society once and for all?

"After the cataclysmic events of 'City At War', the Turtles find New York City drastically changed--new factions and enemies are on the rise, and allies are in short supply. The Turtles discover that in order to survive they will need to work together like never before, but when they find themselves separated, Old Hob decides to fill the power vacuum with some very unusual mutants: Zanna, Mushroom, and Zink!"--Provided by publisher.

"Ara is the odd turtle out in his family, preferring his rock collection to new or wild adventures--until he meets Baeoh, a confident tiger who practices martial arts. Unsure if he has what it takes to join Baeoh's taekwondo team, Ara must learn how to come out of his shell, persist through failure, and accept the help of his new friends to complete the Tiger Fitness Challenge"--Back cover.