Now hear this! Now hear this! All hands man your battle stations.

Enemy submarines have been detected in your waters. You command a destroyer which can launch as many as four depth charges at a time. Your mission is to sink as many enemy subs as possible.

But it’s not that simple. Because SUB-SCAN is more than a shooting match. It’s a game of strategy. A battle of wits. Can-and-mouse on the high seas between the hunter above and the hunted below.