DON RECRUITS CHARLIE'S HELP WHEN THE DAUGHTER OF A FELLOW MATHEMATICIAN IS KIDNAPPED AND HELD FOR RANSOM, ON "NUMB3RS," FRIDAY, FEB. 18

Neil Patrick Harris ("Doogie Howser, M.D.") Guest Stars

"Prime Suspect" -- Don needs Charlie's help to find out why the daughter of a mathematician is kidnapped, on NUMB3RS, Friday, Feb. 18 (10:00-11:00 PM, ET/PT) on the CBS Television Network. Lesli Linka Glatter directed the episode written by Liz Friedman.

Neil Patrick Harris ("Doogie Howser, M.D.") guest stars at Ethan Burdick, a man whose daughter is held ransom in exchange for the solution to a highly advanced math equation.

When a 5-year-old girl is kidnapped from her birthday party, Don and Terry lead the investigation but must rely on Charlie's help, as the girl's father, Ethan, is also a mathematician. Charlie realizes the kidnapper's motive when Ethan reveals that he is close to solving Riemann's Hypothesis, a difficult math problem. If solved, the solution could not only earn him with $1 million but could break the code for Internet security, unlocking the world's biggest financial secret.

Don Eppes: Rob Morrow
Charlie Eppes: David Krumholtz
Alan Eppes: Judd Hirsch
Terry Lake: Sabrina Lloyd
David Sinclair: Alimi Ballard
Larry Fleinhardt: Peter MacNicol
Amita Ramanujan: Navi Rawat
Ethan Burdick: Neil Patrick Harris
Becky Burdick: Susan Egan
Emily Burdick: Emma Prescott
Carl Mittendorf: Greg Zola
Mikey: Ian Barford Dr. Stephen Atwood: Tom Irwin
Paul Ballard: Jamie McShane
Kyono: Fay Wolf Meredith: Murphy Cross
Parole Officer: Michael J. Cutt
FBI Computer Tech #1 Matthew: Yang King
FBI Computer Tech #2: Susan Beaubian
FBI Computer Tech #3: Mauricio Mendoza

RATING: TVPG-V