It's a very special day for Michelangelo... only his brothers seem to have forgotten all about it. Unknown to Mikey, the other Turtles are only pretending that they have no idea it's his birthday, in order to launch a surprise party on him later. As the day progresses, and Michelangelo gets more and more irritated and upset, Leonardo begins to feel as if he, Raphael, and Donatello are stretching the joke just a little too far. But his concerns are ignored by the others, who believe Michelangelo's present state will make his surprise party even better. Michelangelo, depressed and frustrated, surprises them all before they can surprise him…by running away! Before they can go after him, the remaining TMNT hear reports of Shredder, Rocksteady, and Bebop, embarking on a rampage through New York