(SPOILERS BELOW)

After watching enough old movies, I’ve become convinced that the early 1970s must have been the darkest and most cynical time in American history.  It seems like almost every film released from roughly 1970 to 1977 was required to end on a down note.  Even the happy endings were full of ambiguity.  (American Graffiti, a feel-good film according to the reviews that were written at the time of its initial release, ends with one of the characters dying in a car accident and another one MIA in Vietnam.)  I’m not complaining, of course.  I love a sad ending.

Maybe that’s why I so love the 1973 film The Sister-in-Law.  The film starts out as a typical melodrama from Crown International Pictures but it has one of the darkest endings that I’ve ever seen.  In fact, the ending is so dark that it’s pointless to review The Sister-in-Law without telling you how the movie ends.  So, consider this to be your final SPOILER WARNING:

Okay, ready?

Robert Strong (played by John Savage) is a genuinely likable musician who has spent the last year or so hitchhiking across America.  He decides to visit his wealthy older brother, Edward (Will MacMillan).  It quickly becomes apparent that Robert and Edward are almost insanely competitive with each other.  A friendly day of fun in the pool ends with Edward nearly downing his younger brother.

Robert gets back at Edward by having an affair with Edward’s wife, Joanna (Anne Saxon).  However, Robert eventually breaks things up with Joanna and starts sleeping with Deborah (Meredith Baer), who happens to Edward’s former mistress.

Edward, however, has problems beyond dealing with his wife and his mistress.  It turns out that he’s made all of his money by smuggling drugs into America from Canada.  Now, the Mafia is demanding that Edward bring in a huge shipment of heroin.  Edward, however, convinces his brother to do it for him.

Robert and Deborah drive up to Canada and pick up the heroin.  However, as they do so, they talk about how sick they are of being used by Edward.  So, Robert and Deborah pull over next to a waterfall and, in a surprisingly lyrical scene, they dump all the heroin into the water supply.

And then they make love in the forest.

Well, the mafia wants to know what happened to their heroin.  So, Edward and Joanna get on an airplane and flee the country.  Meanwhile, Robert and Deborah are pulled over by two gangsters.  Robert is pulled out of the car and executed in the middle of the street.  The gangsters drive away.  Deborah collapses to her knees and sobs over Robert’s dead body.

The end.

Seriously, that’s how the movie ends.  The gangsters get away with it.  Hateful Edward and his self-centered wife escape the country.  Deborah is in tears.  And Robert, the one truly likable person in the entire film, lays dead in the street.

Not even David Fincher could make a film this dark.  And, honestly, the darkness at the heart of The Sister-in-Law feels considerably more potent and tragic than anything you could find in any Fincher film.  As played by a very young John Savage (who, just last year, played the President in Bermuda Tentacles), Robert is such a likable guy that you’re glad you got to spend a little bit of time with him before he was brutally murdered in the middle of the street.  Robert’s violent death sticks with you.

(Savage also sung several of the surprisingly catchy songs on the film’s soundtrack.)

Despite or perhaps because of the ultra-dark ending, The Sister-in-Law is one of my favorite Crown International films.  If nothing else, it proves that 1973 was apparently even darker than 2015.