November 1943 – January 1944. German U-515 under command of Werner Henke, defies the odds, escapes Allied depth charges and aircraft to sink ships and return to port. At a time when becoming a U-boat Ace was nearly impossible, Henke thrives and sinks Allied ships when many others do not survive their first patrol.
March 1944. U-515 under Henke, departs from Lorient, France bound for the African Gold Coast to target Allied shipping. That same day, USS Guadalcanal, part of the US Navy’s new Hunter-Killer Task Force 21.12, sets sail from Casablanca, about 1,000 miles south.
US Navy’s Captain Daniel Gallery, a Bronze Star recipient, is charged with leading the expedition and captaining USS Guadalcanal, an escort carrier, carrying some 23 Avenger and Wildcat aircraft, screened by four destroyer escorts. The sole purpose of the new Hunter-Killer Task Group: prevent German U-boat resurgence.
Gallery’s first night-flight experiment results in the first point of contact between U-515 and USS Guadalcanal. Signifying the start to a game of naval cat and mouse.
April 9th, 1944. Easter Sunday. Although Henke knows he is being stalked, U-515’s batteries are running out of power so he surfaces. Almost immediately an Avenger is on top of them dropping depth bombs. U-515 crash dives to escape the attack.
Wanting to catch and kill his prey, Gallery orders destroyer escorts USS Pillsbury and USS Flaherty to engage the enemy with a new weapon called “The Hedgehog.” Pillsbury launches two Hedgehog attacks forcing the U-boat to a depth of 720 feet, about 120 feet below maximum diving depth. In a desperate attempt to divert their destroyer hunters, Henke uses the Bold – decoy bubbles – and it works, but not for long.
An unrelenting Gallery calls in two additional destroyer escorts to assist: USS Chatelain and USS Pope. Pope’s sonar locates U-515 and launches the first of two Hedgehog attacks, both miss. Plan B: Pope deploys a continuous pattern of depth charges, and these hit. Despite all efforts to regain control of the sinking U-boat, Henke gives orders to abandon ship.
In exchange for assistance with intelligence investigations, which he later recants, Henke is to be transferred to a POW camp in Canada. Although Henke miraculously survives at sea, he is shot and killed on land while trying to escape Fort Hunt, an POW interrogation center.