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Russell Contreras, Associated Press
Jill Flint prepares for a scene on the set of NBC's "The Night Shift," at Albuquerque Studios in Albuquerque, N.M., Thursday, Feb. 19, 2015. Last summer’s surprise hit returns for a second season Monday, Feb. 23, and producers hope its diverse cast will keep viewers coming back.

ALBUQUERQUE, N.M. — Last summer's surprise NBC hit "The Night Shift" returns for a second season Monday, and producers hope its diverse cast will keep viewers coming back.

Set in San Antonio and filmed in Albuquerque, the drama stars Dublin-born Eoin Macken, who plays Dr. TC Callahan, and Chicago-bred Freddy Rodriguez, who plays hospital leader Michael Ragosa, as they try to run an emergency room in a largely Mexican-American city.

It also stars Jill Flint, who plays Dr. Jordan Alexander, and Ken Leung, known for his roles in "Lost" and the "The Sopranos."

Co-creator Gabe Sachs says producers picked stronger actors who they thought would best represent the real diversity of a hospital.

The Sony Pictures Television production surprised critics last summer when it averaged around 6.9 million viewers per episode.