MEREDITH AND DEREK WORK ON THEIR LAST PATIENT IN THEIR CLINICAL TRIAL, AS THE OTHER SURGEONS TRY DESPERATELY TO FREE A BOY FROM A HARDENING BLOCK OF CEMENT, ON A TWO-HOUR "GREY'S ANATOMY"

Amy Madigan ("Gone Baby Gone") Guest Stars

"Freedom" Parts 1 & 2 � On a two-hour edition of "Grey's Anatomy," Meredith and Derek have one last shot at a successful outcome in their clinical trial, as the other surgeons work together to free a boy from a hardening block of cement. Meanwhile, Izzie helps Alex care for an ailing Rebecca, and Lexie discovers critical information about George's intern status, on "Grey's Anatomy," THURSDAY, SEPTEMBER 18 (9:00-11:00 p.m., ET) on the ABC Television Network. (Rebroadcast. OAD 5/22/08)

"Grey's Anatomy" stars Ellen Pompeo as Meredith Grey, Patrick Dempsey as Derek Shepherd, Sandra Oh as Cristina Yang, Katherine Heigl as Isobel "Izzie" Stevens, Justin Chambers as Alex Karev, T.R. Knight as George O'Malley, Chandra Wilson as Miranda Bailey, James Pickens, Jr. as Richard Webber, Sara Ramirez as Callie Torres, Eric Dane as Mark Sloan, Chyler Leigh as Lexie Grey and Brooke Smith as Erica Hahn.

Guest starring Amy Madigan as Dr. Wyatt, Elizabeth Reaser as Rebecca, Lauren Stamile as Rose, John Cothran as Ken, James Immekus as Andrew, Kathryn Meusle as Liz, Marshall Allman as Jeremy, Jana Kramer as Lola, with Loretta Devine as Adele, and Jurnee Smollett as Beth. Co-Starring Christian Alexander as Will, Stephen Bishop as firefighter, Molly Kidder as intern Megan, Sterling Knight as Kip, Joy Osmanski as intern Lucy and Jerry Zatarain Jr. as David.

"Freedom" Parts 1 & 2 were written by Shonda Rhimes and directed by Rob Corn.

"Grey's Anatomy" is broadcast in 720 Progressive (720P), ABC's selected HDTV format, with 5.1-channel surround sound and Spanish subtitles via secondary closed captioning. This program carries a TV-14,S parental guideline.

This episode of "Grey's Anatomy" will be available on ABC.com the day after airing on the network for users to watch online.