When human sailors are attacked by mysterious creatures of the deep, only one person can stop the war between land and sea: the Witcher, Geralt of Rivia.

After supervillain Shredder escapes custody, he joins forces with mad scientist Baxter Stockman and two dimwitted henchmen, Bebop and Rocksteady, to unleash a diabolical plan to take over the world. As the Turtles prepare to take on Shredder and his new crew, they find themselves facing an even greater evil with similar intentions: the notorious Krang.