Watch Darkest Hour (2017) HD Full Movie Free on SolarMovie. Watch Darkest Hour (2017) online free. In May 1940, the fate of World War II hangs on Winston Churchill, who must decide whether to negotia...In May 1940, the fate of World War II hangs on Winston Churchill, who must decide whether to negotiate with Adolf Hitler, or fight on knowing that it could mean the end of the British Empire.