Captain Fitzgerald (Alec B. Francis), a retired guardsman on a modest pension, has to support three daughters: Theodora (Swanson) and her older half-sisters. Theodora's sisters pin their hopes on her marrying a wealthy man.
One day, Theodora goes out on a rowboat off the coast of Dorset and falls into the water. She is rescued by Lord Hector Bracondale (Valentino). He is young, handsome and wealthy, but "not the marrying kind". Out of a sense of duty to her beloved father, she reluctantly agrees to wed the middle-aged, short, stout Josiah Brown (Robert Bolder), a former grocer's assistant who is now a multi-millionaire.
They honeymoon in the Alps. By coincidence, Bracondale stops at the same inn. Rich American widow Jane McBride (Mabel Van Buren) persuades the young bride to accompany her on a climbing excursion. Theodora slips and dangles precariously by her safety line over a cliff. Bracondale appears and climbs down to her, but they are too heavy for the others to pull up. Bracondale has them lower him and Theodora to a ledge below. While they wait for more help to arrive, Theodora tells Bracondale (who does not initially recognize her) where they last met.
They meet a third time in Paris, and finally acknowledge their love for each other. However, Theodora refuses to run away with Bracondale.
Bracondale strives to do the right thing. He asks his sister, Lady Anningford (June Elvidge), to befriend Theodora. Lady Anningford invites the Browns to her country estate. Bracondale, however, cannot stay away. He tries once again to persuade Theodora to change her mind, without success. Meanwhile, Josiah is persuaded by another guest, renowned explorer Sir Lionel Grey, to fund his dangerous expedition. Bracondale leaves, and Josiah is called away on business. Theodora writes a letter to each; to Bracondale, she declares her love, but stresses once more that it cannot be fulfilled. Morella Winmarleigh (Gertrude Astor), who desires Bracondale for herself, secretly opens the letters and, after perusing them, switches them.
After Bracondale reads the message meant for Josiah, he rushes to stop Josiah from reading his, but is too late. Josiah accuses Bracondale of stealing his wife, but the nobleman denies that Theodora has been unfaithful.
After further consideration, Josiah decides to put his wife's happiness ahead of his own and joins Grey's expedition to Northern Africa. His death makes it possible for the young lovers to be together.
While the book mostly takes place at dinner parties, picnics and balls, the film version changes many of the events to take place during perilous outdoor sports. Relatedly, the book's Bracondale never saves Theodora's life, as there is no particular danger for her to get into. Josiah in the book is chronically ill and dies after a long period of health problems; in the film he dies relatively quickly in a hunting accident. The film also has added historical sequences, inspired by Cecil B. DeMille's work. Director Sam Wood had been an assistant director for DeMille.Rudolph Valentino as Lord Hector Bracondale
Gloria Swanson as Theodora Fitzgerald
Edythe Chapman as Lady Bracondale, Hector's mother
Alec B. Francis as Captain Fitzgerald
Robert Bolder as Josiah Brown
Gertrude Astor as Morella Winmarleigh
June Elvidge as Lady Anna Anningford
Mabel Van Buren as Jane McBride
Helen Dunbar as Lady Ada Fitzgerald
Raymond Brathwayt as Sir Patrick Fitzgerald
Frank Butler as Lord Wensleydon (as F. R. Butler)
Beyond the Rocks was considered a lost film, save for a one-minute portion, for the better part of the twentieth century until a print was found in the Netherlands in 2003. The film was restored by the Nederlands Filmmuseum and the Haghefilm Conservation. It turned up among about two thousand rusty film canisters donated by an eccentric Dutch collector, Joop van Liempd of Haarlem. It was given its first modern screening in 2005.
The restored version was released on DVD in 2006.