Greyhound is a 2020 American war film directed by Aaron Schneider and starring Tom Hanks, who also wrote the screenplay. The film is based on the 1955 novel The Good Shepherd by C. S. Forester, and also stars Stephen Graham, Rob Morgan, and Elisabeth Shue. The film follows a US Navy commander on his first assignment commanding a multi-national escort destroyer group of four defending an Allied convoy of thirty-seven ships from German U-boats in early 1942 during the Battle of the Atlantic, shortly after the United States has officially entered World War II.

Plot

In February 1942, convoy HX-25, consisting of 37 Allied merchant and troop ships, making its way to Liverpool, enters the "Black Pit", the Mid-Atlantic gap, where they will be out of range of protective air cover for the next five days. The convoy's escort consists of the USS Keeling (DD-548), radio call sign "Greyhound", captained by Commander Ernest Krause of the United States Navy; the British Tribal-class destroyer HMS James F80, call sign "Harry"; the Polish ''Grom''-class destroyer ORP Viktor H34, call sign "Eagle"; and the Canadian , HMCS Dodge K136, call sign "Dicky". Krause is overall commander of the escort ships, but despite his seniority and extensive naval education, it is his first wartime command. Three days later, High-frequency direction finding from the convoy flagship intercepts a German transmission and Greyhound identifies a surfaced U-boat heading towards the convoy and moves to attack. The sub tries to slip under Greyhound, but Krause sinks it with a full pattern of depth charges to the crew's jubilation.