The Justice Force is expanding its ranks, and Mike plans on joining up as Turtle Titan!, while Leo is more concerned in alerting them to the threat of the original Shredder. But when Nano reappears (thanks to Bishop and Baxter Stockman), everything quickly spirals out of control into a superhero vs. nanotech slugfest! But has Nano come back as friend or foe? And will the Turtle Titan and Leo survive long enough to find out?