Tom Carson, a southerner, with his daughter, Grace, is the keeper of the Grey Sentinel Lighthouse. John Adams, the sweetheart of Grace, returns from West Point and joins the southern cause; he, however, spying for the Union Army. A fierce battle takes place between the Confederate and Union forces in which the former are victorious. Hal Peters, a southern officer and an admirer of Grace, is surprised to find among his captives. John Adams.