Noah Wyle is back in a big way, reprising his role as Dr. John Carter for the final four episodes of "ER" -- and now saving the world with a third installment of his hit 'Librarian' series. Read on to find out which classic foe he faces!

"I've had more fun making these movies than anything else I've done in my career," Noah tells ET about his 'Librarian' adventures. 'The Librarian: Curse of the Judas Chalice' debuts Sunday night at 8 p.m. on TNT.

This time, Noah's overworked Flynn Carsen heads to New Orleans for a little R&R, instead finding himself tasked with rescuing a professor (Bruce Davison) and fending off bad guys intent on using the silver chalice (given to Judas for betraying Jesus) to resurrect Prince Vlad Dracul himself and raise an army of vampires.

"The Librarian is the only one who can protect the chalice," says Noah.

The action takes place in The Big Easy because, as Noah explains, "When we thought of what area of the country had the best mythology and sense of history, and we identified Louisiana and New Orleans."

Watch ET for more with Noah Wyle!