Watch Bonanza: Under Attack for Free: How to Stream the Movie Online at 123Movies. . After a rogue band of Pinkerton detectives led by ruthless Charley Siringo bushwhacks reformed outlaw Frank James, he seeks sanctuary on the Ponderosa with the next generation of Cartwrights and his former Civil War compatriots. Will Frank's comrades come to his aid or turn their backs on him? Richard Roundtree also stars in this made-for-TV sequel to the popular Western series.