This is the wildest, craziest film ever made. It is set in Madrid and claims to be a true story told by circus people! Alonzo (Lon Chaney) is a killer who is known to the police only by the strange double thumbs on his left hand. So he straps his arms behind his back and joins a travelling circus as a knife act, throwing daggers at Nanon (a very young Joan Crawford) with his feet.
Because of previous abuse, Nanon can't stand to be touched and so is neurotically repulsed by the attentions of circus strong man Malabar (Norman Kerry). As the police close in on Alonzo, to hide his incriminating thumbs and to indulge Nanon's fetishistic attraction to him, Chaney has both his arms removed by a surgeon he is blackmailing!
Unfortunately, when Alonzo returns to the circus, Nanon has got over her fear of Malabar and married him. The now insanely jealous knife thrower devises a hideous revenge! This is pretty uninhibited stuff. The story was created by Tod Browning who left home as a child to join a circus. Chaney's upbringing was equally unconventional.
Many silent horrors have the illusory mania of a febrile dream. And that is the great attraction of The Unknown. And it's a lot of fun watching Chaney acting (brilliantly) with his feet. Browning and Chaney did astonishing work, but there was an alchemy when they worked together. It feels like anything is possible.