Your mission unfolds deep beneath the surface of the ocean waves seek out and destroy six enemy convoys. As the commander of four subs, you've got to stop your foe's convoys from reaching safe harbours otherwise the opposition will grow even stronger. Use the periscope to spot enemy craft then take aim and fire torpedoes. They'll counter-attack with depth charges, guns, and more, so be ready to take shelter in the deep depths of the ocean.