Season 12

SEASON 12 SYNOPSIS Acting on a lead, Sam and Luka drive to Iowa, then on to Colorado in search of runaway Alex. On the road, they discuss their relationship and realize that the end is nigh. When they finally find Alex, Sam tells him the truth about his dad, and takes him to see Steve in prison. Back in the ER, Ray, Neela and Abby struggle to teach their new interns. Pratt reunites with his estranged father Charlie and learns that he has a half brother, Chaz. Neela prepares a care package for Gallant. Sam moves out, and Luka sinks into a depression that carries over to the job. New abrasive nurse manager Eve Peyton isn't blind, so she changes Sam's schedule so she won't work with Luka, but will have to sacrifice time with Alex. Dubenko tells Abby he has prostate cancer, and that his impending surgery may cause erectile dysfunction. He wants to go down swinging, but Abby declines his offer of sex and picks up a drunken Luka instead. Jerry gets struck by lightning.

Weaver is forced to run the ER when new attending Dr. Victor Clemente shows up as a patient to test and berate the staff. He has Abby help him with a baby chimp, who sadly can't be saved. Eve promotes Sam, who is quickly forced to fire Haleh. Ray picks up Zoe at a concert and learns too late that she's 14 and has chlamydia. As a result, Zoe's dad beats up Ray. When a kidnapper and his human shield are brought into the ER, Clemente and Luka war over treatment, and Abby is caught in the middle. Luka puts his name in as a candidate for ER chief, and Clemente takes himself out of the running. Angry over the whole deal, Abby visits Luka, who kisses her. They wake up awkwardly together, and decide to be "just friends."

SEASON 12 CAST Sharif Atkins, John Aylward, Linda Cardellini, Louise Fletcher, Scott Grimes, Laura Innes, Parminder Nagra, Leland Orser, Mekhi Phifer, Sherry Stringfield, Maura Tierney, Goran Visnjic, Shane West

SEASON 12 GUEST STARS Armand Assante, Kat Dennings, Sara Gilbert, Danny Glover, C. Thomas Howell, Ernie Hudson, Kristen Johnson, Diane Ladd, John Leguizamo, Mary McCormack, Sheryl Lee Ralph, John Stamos, Callie Thorne, Natasha Gregson Wagner, Eamonn Walker, Megan Ward, Serena Williams, James Woods, Noah Wyle