Douglas Fairbanks Jr. plays twin brothers on a mission of vengeance in The Corsican Brothers, an excellent swashbuckler I wish I'd heard of sooner.
Set at some point in the early-ish 1800s in Corsica, the Count and Countess Franchi (Henry Wilcoxon and Gloria Holden) have gathered the entire clan together to celebrate the impending birth of their child. The child, however, turns out to be conjoined twin boys that Dr. Paoli (H. B. Warner) works desperately to separate without killing them. As the family celebrates while the doctor does his work, the Franchi family's rival, Baron Colonna (Akim Tamiroff) takes advantage of the celebration to order a massacre of the entire Franchi clan - men, women, and children alike. As the massacre brutally commences, Dr. Paoli, having successfully separated the boys, helps them escape, splitting them up for their safety. The two brothers (both played by Douglas Fairbanks Jr.), the sole surviving Franchis, grow up leading very different lives. One, Mario, goes with the doctor to Paris to be raised as a gentleman. The other, Lucien, is taken by loyal servant Lorenzo (J. Carrol Naish), and he remains in Corsica, growing up as a forest bandit striking out at Colonna. Despite the distance between them, as a side-effect of their having been born conjoined, when one gets hurt, the other can feel it, and they sometimes dream of each other's experiences. Eventually, Mario learns of his true heritage and obligation to avenge his family, and he travels to Corsica to unite with Lucien. Together, they terrorize Baron Colonna, taking down one of his allies and relatives after another before striking at Colonna himself. But when the lovely Countess Isabelle Gravinni (Ruth Warrick) steps into the picture and falls for Mario, Lucien's envy threatens the bond between the two brothers and the completion of their vendetta.