When Truman became president he learned of the new atomic bomb being made. He warned japan that unless they surrendered America would bomb them. Japan didn't respond so the US attacked different cities killing over 140,000 people.
The Germans suffered many losses such as the North African Campaign, Battle of Stalingrad, and Battle of the Bulge Germany had to surrender. The Soviets had Berlin surrounded and Soviet shells burst over Berlin. April 30th Hitler commited suicide.
When the US cracked one of the codes that the Japanese used in secret messages, they soon knew Japan's plans for South East Asia. After being cut off from oil, Japan decided to launch attacks which included attacking Hawaii.
Six months after Chamberlin signs the appeasement at the Mucnich Conference Germany invades Poland, which breaks the treaty. Britain and France try to get the Soviets to sign a Nonagression Pact to help stop Germany. This doesn't work because the Soviets are secretly working with Germany.
Update Sources
