Combat (1927)

As Jack Hammond succeeds in perfecting his invention of a valuable formula, his uncle, Mark Hammond, for whom he has been working, declares it to be his own. Jack decides to fight him in court, but the uncle hires Capt. Samuel Yearkes, a desperado living on the Florida Keys, to do away with Jack. Risa Bartlett, a cafe hostess and admirer of Jack's, decides to lend him the money for a legal battle, but he is lured away to Tostado Island by a bodyguard position offered by Yearkes. There he falls in love with Wanda, Yearkes's ward, but Yearkes tries to influence her against the boy. Meanwhile Risa learns that Jack has been framed by his uncle and flies to Tostado with Craig Gordon, a millionaire suitor, and lands on a pretext. Yearkes's plan to kill Jack is foiled when they escape in his boat; Wanda decides to join them at the last minute.