Two Mules for Sister Sara is a 1970 American-Mexican Western film in Panavision directed by Don Siegel and starring Shirley MacLaine and Clint Eastwood[4] set during the French intervention in Mexico (1861–1867).

The plot follows an American mercenary who gets mixed up with a nun and aids a group of Juarista rebels during the puppet reign of Emperor Maximilian in Mexico.

When Sara declares she cannot climb the high trestle herself to set the charges, Hogan reminds her of her debt to him in saving her life, and she reluctantly complies, enabling them to successfully blow up the train.

In the lead-up to the attack, Sara begs the local villagers for money needed to purchase dynamite for the assault on the garrison, enlisting the help of prostitutes at a brothel.

The ruse works, and Hogan and Sara engage the French commanding officers while the garrison's gates are breached for the Mexican revolutionaries to swarm through.

Now wealthy and with his job completed, Hogan sets off with Sara, now wearing a garish red silk gown and feathers instead of the habit, the romantic couple now intending to open a gambling house in San Francisco.

[8] Budd Boetticher, a long term-resident of Mexico renowned for his series of Randolph Scott westerns, wrote the original 1967 screenplay that was bought with the provision that he would direct.

[12] Boetticher expressed disgust that MacLaine's bawdy character obviously did not resemble a nun, as opposed to his idea of a genteel lady whose final revelation would have been more of a surprise to the audience.

[14] Eastwood had been shown the script by Elizabeth Taylor (at the time, the wife of Richard Burton) during the filming of Where Eagles Dare; she hoped to play the role of Sister Sara.

Although they were initially unconvinced with her pale complexion,[15] Eastwood believed that the studio was keen on MacLaine as they had high hopes for her film Sweet Charity, in which she played a taxi dancer.

[citation needed] Don Siegel describes his struggle to exert control over the filming of Two Mules for Sister Sara: “Marty Rackin [the producer] and I didn’t get along.

[17][25] Stanley Kauffmann of The New Republic described the film as "an attempt to keep old Hollywood alive—a place where nuns can turn out to be disguised whores, where heroes can always have a stick of dynamite under their vests, where every story has not one but two cute finishes.

[26] In a review by the Los Angeles Herald-Examiner, Two Mules for Sister Sara was called "a solidly entertaining film that provides Clint Eastwood with his best, most substantial role to date; in it he is far better than he has ever been.

"[3] Biographer Judith M. Kass concurs: “In Eastwood’s manner Siegel found the filmic mirror of himself, and the mythic anti-hero of the soiled American dream...”[27] Stanley Kauffmann of The New Republic wrote: 'It doesn't matter to Siegel that the characters are cliches, the acting is atrocious, the plot laughable, the dialogue dumb, and the patriotic theme only a peg to hang killings on.