It's Michaelangelo'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. (thetvdb.com)