Watch Greyhound full movie online Movies123. Watch Greyhound 123movies online for free. Greyhound 123Movies: A first-time captain leads a convoy of allied ships carrying thousands of soldiers across the treacherous waters of the “Black Pit†to the front lines of WW2. With no air cover protection for 5 days, the captain and his convoy must battle the surrounding enemy Nazi U-boats in order to give the allies a chance to win the war.