Taglines.
"She Helped Her Husband Destroy His Brother By The Most Immoral Act Imaginable"
"She Kept It All In The Family!"
Plot.
Robert Strong (John Savage), a singer-songwriter who has been traveling the country, makes a mistake when he goes to visit his brother, Edward (Will MacMillan), and gets involved with his bored sister-in-law, Joanna (Anne Saxon).
Robert and his brother's mistress, Deborah Holt (Meridith Baer), try to help his brother get away from working in drug smuggling.
It may or may not be a mistake, which turns out deadly.
Principal cast.
Feature film debut of Anne Saxon, who plays the titular sister-in-law. This is also the only known film appearance by Ms. Saxon. There has been some speculation that she used an assumed name while making the film.
John Savage who starred as the principle lead in this film also provided much of the music. He wrote and performed three original songs for the film.
Michael Ruben: close family member of the film's director, writer, and producer Joseph Ruben appears as the young son of Edward and Joanna Strong.
Home media.
Like other films distributed by Crown International Pictures, "The Sister-in-Law" is readily available through VOD and often included in DVD collections of similar films from the 1970s such as The Pom Pom Girls and Blue Money, through Mill Creek Entertainment and other companies.