In May 1942, submarines begin inflicting heavy damage on Japanese shipping. The marines and Army invade the Gilbert, Marshall and Solomon Islands. In November 1943, American forces, with heavy casualties, take Tarawa. Admiral Nimitz, over many objections, decides to bypass many strongly-held Japanese islands and blockade them to deprive the Japanese of supplies and food. Roosevelt publicly demands "unconditional surrender," and the Japanese dig in their heels to fight to the death. American forces attack the Solomon and Marshall Islands, creeping ever closer to Japan. MacArthur attacks New Guinea. In June 1944, American forces invade the Mariana Islands of Saipan and Tinian, and later, Pelelui. With these islands in American hands, its bombers can reach the Japanese mainland. Saipan and Pelelui are captured with many American casualties. Fighting becomes a vicious no-holds-barred affair. A famous American, now a pilot, is rescued by submarine, after his plane crashes into the sea.