Here's the official synopsis for the sequel, titled 'Muppets Most Wanted':
Disney's 'Muppets Most Wanted' takes the entire Muppets gang on a global tour, selling out grand theaters in some of Europe's most exciting destinations, including Berlin, Madrid and London. But mayhem follows the Muppets overseas, as they find themselves unwittingly entangled in an international crime caper headed by Constantine—the World's Number One Criminal and a dead ringer for Kermit—and his dastardly sidekick Dominic, aka Number Two, portrayed by Ricky Gervais.
Directed by James Bobin and produced by David Hoberman and Todd Lieberman, the film also stars Tina Fey as Nadya, a feisty prison guard, and Ty Burrell as Interpol agent Jean Pierre Napoleon. 'The Muppets Most Wanted' is due out on March 21, 2014.