The white heather (1919)

Lord Angus Cameron's marriage to a woman of his titled Scottish class is thwarted by his secret marriage years before to Marion Hume, the housekeeper of the castle. Cameron attempts to repudiate the marriage, the only record of which is a certificate in the sunken wreck of a yacht, The White Heather. Marion goes to court to prove her claim and secure the rights of her son by Cameron, but is defeated. Alec McClintock, who is in love with Marion, and Cameron both want to recover the record, so they don diving suits and descend to the wreck. An underwater struggle ensues and Cameron severs his own air tube and drowns while attempting to cut off his rival's air supply. Alec then recovers the marriage record and wins Marion. —AFI