While preparing for Irma's birthday party, Michaelangelo realizes he has forgotten to invite the guest of honor. He contacts April, who is in the midst of interviewing Professor Von Zifflein about the discovery of a meteorite that "just crashed in the area." The professor claims that this is a very unusual meteorite with a core composed of an extremely rare isotope known as 'Exaporon'. The Turtles turn on their TV to watch their favorite journalist as she interviews the professor. Suddenly a noxious gas fills the room and someone steals the meteorite. Before the thief can escape, he stops in front of the news camera, revealing himself to be Shredder. (thetvdb.com)