THE ROOKIES TRY TO HUNT DOWN A VIGILANTE IMPERSONATING AN OFFICER, AND ANDY AND SAM'S FORBIDDEN ROMANCE THREATENS SWAREK'S ENTIRE UNDERCOVER OPERATION, ON ABC'S "ROOKIE BLUE"

"On the Double"- When Gail's uniform is stolen from her car, she and the other rookies from Division 15 attempt to catch a cop-impersonating vigilante. A drug deal gone awry may offer clues to help Chris and Dov unravel the motive behind the cop masquerade. Meanwhile, Andy and Sam's inability to stay away from each other poses a life-threatening risk to Swarek, on "Rookie Blue," THURSDAY, SEPTEMBER 8 (10:00-11:00 p.m., ET), on the ABC Television Network.

"Rookie Blue" stars Missy Peregrym as Andy McNally, Gregory Smith as Dov Epstein, Charlotte Sullivan as Gail Peck, Enuka Okuma as Traci Nash, Travis Milne as Chris Diaz, Ben Bass as Sam Swarek and Eric Johnson as Detective Luke Callaghan. Also starring in the series are Melanie Nicholls-King as Noelle Williams, Matt Gordon as Oliver Shaw, Noam Jenkins as Detective Jerry Barber and Lyriq Bent as Frank Best.

Guest starring in "On the Double" is Aaron Abrams as Donovan Boyd, Callum Keith Rennie as Jamie Brennan, Landon Norris as Danny Blake and Kristina Pesic as Lindsay Blake.

"On the Double" was written by Ellen Vanstone and directed by Peter Wellington.

"Rookie Blue" is broadcast in 720 Progressive (720P), ABC's selected HDTV format, with 5.1-channel surround sound. A TV parental guideline will be assigned closer to the airdate.

This episode of "Rookie Blue" will be available on ABC.com the day after airing on the network for users to watch online.

For more information on "Rookie Blue," please visit ABC.com.