While there were often disasters such as floods, fires, and avalanches in silent films, few of them were actually built around a catastrophic event. This melodrama focused on the Johnstown flood, which destroyed the Conemaugh Valley in 1889, making it an ancestor of modern-day disaster films. Janet Gaynor, in a supporting role, had recently worked her way up from Hal Roach comedies and was clearly headed for stardom. Contractor John Hamilton (Anders Randolph) has built a dam above Johnstown over the protests of his engineer, Tom O'Day (George O'Brien), who is convinced the structure is weak and dangerous. O'Day is in love with Hamilton's daughter, Gloria (Florence Gilbert), and they wed while her father is in Pittsburgh. Right on schedule, the dam bursts. Ann Burger, a little local girl (Gaynor), is drowned while riding on horseback to warn the villagers. O'Day and Gloria manage to make it out alive.
by Janiss Garza synopsis