Watch Hell Below for Free: How to Stream the Movie Online at 123Movies. . On leave in Italy, Lt. Tommy Knowlton falls in love with Jean Standish, who's not only married, but is the daughter of his submarine's commander. Friction between the two officers becomes intolerable once at sea and after Commander Toler is forced to abandon Tommy's best friend topside while the sub dives to escape enemy planes, Tommy is no longer able to contain his anger.