Conrad Veidt plays Gwynplaine, the orphaned child of a dissident noble during King James II's rule, whose face is carved into a hideous smile, and makes a wretched existence as a clown in a travelling show. What makes him stay is the love of the blind girl he rescued in the snow, and his own disgust at his ravaged face. Billed in the carny as "The Man Who Laughs" Gwynplaine has the ability to make any local rabble laugh at his ghoulishly smiling face--except for an evil countess who he encounters in his old town. This leads to problems with his love, as he's torn between the woman who's never seen his face, or the one who's intrigued with him despite his affliction.
The fact that, unbeknownst to him, she's living on his lost estate complicates things even further.
It's high melodrama of the "melo-est" sort, and Leni crafts it with an artists' eye for lighting, and a trickster's way with camera movement. It's far more subtle than most films of the silent era, while glorying in the dramatic gestures of the era, and makes for a compelling fusion of the German and American film sensibilities.