The Phantom Melody (1920)

Count Camello lives on his fine estate in Italy, near the home occupied by Sir James Drake and his family. Gregory Baldi, a parasitical cousin of the count, is courting Mary Drake, and although the count also loves the girl, he conceals his feelings out of respect for his cousin. When war breaks out, Camello enlists while Gregory convinces Mary's brother Oliver that Oliver has killed an opponent in a duel and that the only way to escape a murder charge is to disguise himself by going to war under Gregory's name. Wounded, Count Camello returns from the front and, after Gregory is reported dead, proposes to Mary. On the eve of their wedding, Gregory returns unexpectedly and, in dire need of money, buries his cousin alive in the family vault. The count escapes and disguises himself to watch over Mary. Meanwhile, Oliver returns, having discovered Gregory's duplicity, and in the ensuing fight between them Gregory is killed, thus freeing Mary to turn to the count.