Alonzo (Lon Chaney) is an armless circus performer who entertains crowds by expertly throwing knives with his feet. He’s in love with his partner Nanon (Joan Crawford), the daughter of the circus’s owner, who after years of being groped and pawed at, has grown to loathe being touched by men. Alonzo is one of the few men she can trust because he isn’t able to touch her the way other men can. However, she doesn’t love him the same way he loves her; she’s in love with Malabar (Norman Kerry), the circus’s strongman, and Malabar adores her back.
What Nanon and the other circus performers don’t realize is that Alonzo isn’t actually armless. He is a criminal on the run from the law who has a very distinctive thumb, so he decided to avoid the police by binding his arms to his sides with a corset and pretending to be armless. When the owner of the circus discovers the truth about Alonzo, Alonzo strangles him to death. Nanon witnesses the incident, but the only thing she can distinctly see is her father’s assailant’s unusual thumb. Since all the other circus performers believe Alonzo is armless, he avoids suspicion yet again.
Alonzo is still deeply in love with Nanon, but the only person who knows Alonzo’s secret warns him that they can never be together because she will eventually discover his secret and learn the truth about who killed her father. Desperate to be with her, Alonzo has his arms amputated for the sake of keeping his secret. Meanwhile, Malabar has managed to help Nanon move past her fear of being touched by men and they decide to get married and Malabar starts working on an idea for a new act.
When Alonzo hears Nanon’s news, he is shocked and absolutely devastated. But when Alonzo finds out about Malabar’s new act, he thinks of a way to sabotage the act so he’ll be able to have Nanon for himself.
Although it’s easy to look at The Unknown now and think how great it is to see two of Hollywood’s greatest stars together on screen, it’s important to remember that Joan Crawford wasn’t quite a big star yet at the time she made it. She was still pretty early in her career and The Unknown is definitely one of her first really great movies. In fact, she often talked about how making that movie was a hugely important stepping stone in her career because she was able to learn so much about acting by working with Lon Chaney.
The Unknown was absolutely perfect material for Lon Chaney; I truly can’t think of another mainstream actor who could have played that role as well as he did. Joan’s great in it, too. Since Joan’s silent film career is pretty defined by Our Dancing Daughters and playing a lot of very exuberant, youthful flapper characters, The Unknown offers a chance to see her doing something considerably darker and more complex, which I really enjoyed getting to see. The movie is very fast paced and full of incredible tension and drama; I absolutely love this movie.