Shock

Captain Bob Hayworth, his brother Lieutenant Gilroy Hayworth and Captain Derek Marbury are in a World-War 1 trench on the front-lines in France. Bob Hayworth resents Marbury greatly as the latter had married the girl, Lucy Neville, Marbury was courting in pre-war London. Ordered to go on a night patrol, the cowardly Gilroy committed suicide rather than face his fear. Bob and Derek arrange it to appear that Bob had been killed by a shell-burst, and Derek, with his face camouflaged, takes the patrol posing as Gilroy. While on patrol, Derek is hit by a shell-burst and found by the German Red Cross, who turn him over to a family of French peasants. Weeks later, Drek awakens in an English field-hospital and has amnesia. Since he had no papers on him when found, the hospital staff name him Private John Drake, and he is shipped back to England several months later. There, he is recognized by Bob Hayworth, who has been courting the widow Marbury. Despite the fact that Marbury had undertaken the mission on order to keep the Hayworth family-name from shame, Bob brings charges of battlefield desertion against Derek. The latter, not even knowing who he really is, has no defense against the charges. - IMDb