Alex McArthur, who played a paranoid-schizophrenic in the movie "Rampage" and Madonna's hunk-of-a-boyfriend in her video "Papa Don't Preach," is the hero.

Robert Foxworth, who worries about "redeeming social value" and works with Central American refugee groups, is the villain.

And the theme of NBC's "The Return of Desperado" Monday is justice.

McArthur plays Duell McCall, a roving cowboy who tries to save a group of homesteaders from being snookered out of their land.

"I have a ball making these movies," said McArthur, who plays McCall in all of them. The third "Desperado" will show up in March, with a series in the works if the ratings justify it.

"It's a lot like 'The Fugitive' or 'Wanted: Dead or Alive' -- a man who's accused unjustly," said the lanky McArthur. "The price on my head keeps getting higher. One nice thing about the character: He's becoming seasoned, a little more cynical, a lot tougher."

In contrast to the psychopath he played in "Rampage," and the high school football star sent to a mental institution for killing his girlfriend in CBS' "Intent to Kill," McArthur said he enjoyed playing the part of the cowboy hero, "someone wholesome who didn't mess up my mind."

McArthur, 29, left tiny Telford, Pa., near Allentown "because I wanted to see a little bit of the world." He was attending a community college near San Jose when friends suggested he try acting. He began with four plays in two years with the San Jose Repertory Theater, then appeared in the TV movies "Silent Witness" and "Crimes of Innocence," in "Knots Landing," "Riptide," "Scarecrow and Mrs. King" and "Hill Street Blues" and in the theatrical film "Desert Hearts."

But he recognizes that his few minutes in the Madonna video last year -- which required only three days of his time and no dialogue -- may have done more for his career than all 10 years' of acting. Within days after the video's premiere, he received fan mail and phone calls and roles to consider.

One was the role of Duell McCall. McArthur, who rides motorcycles and horses and is an experienced hunter, varies between first- and third-person when he talks about McCall.

"In this one," said McArthur, describing the plot, "he's hunting for this guy who can clear his name because he's been accused unjustly of crimes and has a price on his head ... He's bushwacked by a bounty hunter and my life is saved by this black cowboy -- Victor Love, who does a very good job -- who is with the 9th Cavalry. Billy Dee Williams is in charge of them ... I come in to this town, Beauty, and the stable boy says this man killed the newspaper editor and is going to be hung ...

"Dryden is an ex-soldier who has a group of henchmen, and he has the whole town's confidence, and says the railroad is coming through ... We end up conquering Dryden and exposing him as as a fraud." You get the idea.

Foxworth, who left "Falcon Crest" after playing Chase Gioberti since the 1981-82 season, is the villainous Marcus Dryden.

"It's kind of good to get back in the saddle," said Foxworth, a Texan. "I am the bad guy in three episodes. I play Col. Marcus Dryden, who was an officer in the Union Army and brought a group of men out West after the Civil War and really sold himself as a guardian of peace and prosperity for this town of Beauty when in actuality he is taking over. It's kind of fun.

"The thing about the show is that it's very traditional: It's the mistaken identity of the hero and the mistaken identity of the bad guy, and the pretty girl in jeopardy. This one has the added situation about a black cavalry unit who have retired their guns, who are tired of fighting, who get drawn into this evil situation. It's got some redeeming social value."

Redeeming social value is something that matters to Foxworth, 46. An actor since he first appeared in the '59-'60 season of Houston's Alley Theatre, he also directed 15 episodes of "Falcon Crest." He has continued to produce and host a twice-monthly, issues-oriented show, "American Dialogues," on National Public Radio since 1985.

For the past five years he has worked with two refugee organizations that provide legal aid, housing and medical help for Central American refugees. In 1985, he was honored by the League of United Latin-American Citizens.

"I am very much opposed to the Reagan administration's policies in Central America," he said. "I felt that I should do something, that here I was a fortunate citizen of this country ... My parents were very conservative, very patriotic, and they instilled in me a sense about my responsibilities as a citizen."

Foxworth said he comes to Washington periodically "to lobby on the Hill," but recalled his earlier days here performing at Arena Stage from 1965 to 1968 while his wife tended to their young son and daughter. "It was a very interesting time to be in Washington," he observed.