With the addition of Glenn Close to its already excellent cast, The Shield entered its fourth season with tensions high and tempers flaring. Aceveda (Benito Martinez) has gained political clout on the City Council, and former Farmington district officer Monica Rawling (Close) is introduced as the new Captain of "the Barn," where she immediately confronts a maelstrom of personal and professional turmoil. His strike team now splintered, Mackey (Michael Chiklis) has returned to routine detective duty, while Shane (Walton Goggins) and new partner "Army" Renta (Michael Peña) are neck-deep in trouble with Farmington's "untouchable" drug-lord, Antwon Mitchell, a new villain played to perfection by actor/comedian Anthony Anderson. This seemingly traitorous predicament places Shane at further odds with former strike-teammates Mackie, Lemon (Kenneth Johnson) and Ronnie (David Rees Snell), and while Wyms (CCH Pounder) resents Rawling's promotion, the "Dutch" (Jay Karnes) makes a selfish backroom deal that causes further friction with Wyms and Mackey. Tensions are intensified by Rawling's aggressive seizure of homes and property paid for with drug money -- an effective campaign that forces "Danny" (Catherine Dent) and Julien (Michael Jace) and the entire police force to take sides in a hotly divisive civil rights debate that culminates in the murder of two Farmington cops.