Are you ready for the grimmest Western ever? The 12-episode series “Deadwood” (9 p.m. Sunday, HBO) brings a touch of “Oz” and “The Sopranos” to the fabled land where the buffalo roamed. For starters, it’s the most energetically profane horse opera ever filmed. I tried to count the number of times the “F” word was used, but I couldn’t keep up. Besides, I was distracted by even more powerful and ugly language, and that was only in the first 10 minutes.

“Deadwood” takes place in 1876, only weeks after the disaster at Little Big Horn. Located in South Dakota’s Sioux territory, the town of Deadwood offers drifters, crooks and gold prospectors a legal and moral purgatory where they can squander their money in whorehouses and saloons. Oh, I forgot to mention, most of the action here takes place in a brothel.

Ian McShane turns in a memorable performance as Al Swearengen, the heartless proprietor of the above-mentioned institutions. Keith Carradine looks great as gunslinger and gambling addict Wild Bill Hickok. Other notable characters in this sprawling cast of doomed travelers include Brad Dourif as the town’s corrupt doctor, Paula Malcomson as a frequently beaten prostitute, and Powers Booth as Al’s rival and the local vice lord.

While I’ve never liked phony Westerns like “Dr. Quinn, Medicine Woman” that use the era as an antiseptic backdrop for heroes and heroines riding around in Eddie Bauer outfits, “Deadwood” is so obsessed in wallowing in human ugliness that it often approaches brutal parody. The production values are superb and many of the performance are fine, but the subject matter often falls outside my personal parameters of “entertainment.” I had similar feelings and misgivings about “Oz.” Help yourself.

Tonight’s highlights

• The NCAA Basketball Tournament (6 p.m., CBS) continues.
• The music of Phil Collins animates the 1999 cartoon musical “Tarzan” (7 p.m., ABC).
• Approaching middle age, three pals (Luke Wilson, Will Ferrell and Vince Vaughn) form their own fraternity in the 2003 comedy “Old School” (7 p.m., HBO).
• A new set of eyes may disqualify a ballplayer on “Century City” (9 p.m., CBS).

Sunday’s other highlights

• Scheduled on “60 Minutes” (6 p.m., CBS): former White House counterterrorism adviser Richard Clarke.
• Tyra Banks guest stars on “American Dreams” (7 p.m., NBC).