High contrast, blurry images In a rigid test of strength the entire battle force of the navy and the defense units at Pearl Harbor take part in the gigantic mimic invasion of the islands. Battleships, cruisers, destroyers, airplane carriers, infantry, marines, and sailors participate in the stirring activities. Under an artillery barrage the invading 'blue' unit lands troops on the objective held by the 'black' defenders. For the first time the entire line of the American sea strength is brought into action.