It's Michelangelo's birthday, but none of his brothers seem to remember, and it frustrates him greatly. Meanwhile, Shredder and Krang discover what is possibly an "anti-mutagen" that, after testing it on three rock soldiers, can undo mutations. Shredder, Bebop and Rocksteady are sent to use it on the Turtles, and our heroes have a few close calls.

Someone is stealing all the kimonos in the city. After Master Splinter's favorite kimono is stolen, April's famous detective aunt helps the Turtles retrieve it.