Oscar Krug returns to his home in Maine after being at sea for a number of years. He reminisces back to just before the war broke out, when he was in love with Alice Morse, daughter of the local banker. Being German, Krug was falsely accused of being sympathetic to the enemy. He enlisted, secretly married Alice, and became Captain of a merchant marine ship. Alice came aboard the ship, which was eventually sunk by a German U-boat. Krug and Alice survived, but the German commander took Alice aboard his vessel, leaving Oscar adrift. Krug swore to the German that he would get revenge. A few months later, Krug's ship fired on a U-boat. Krug recognized the Captain and saved him, although the Captain did not recognize Krug. Krug plied him with liquor and pretended to be a German sympathizer, in order to discover what had happened to Alice. Krug then took his vengeance in a most horrible manner.

This is a stunning piece of work. It begins with ordinary life in a Maine seaport, and lulls the viewer into believing this will just be another romance. The film takes a sharp turn into tragedy, and builds to a grotesque conclusion - strong stuff for any time period, let alone 1919. Bosworth, though perhaps a bit too old for the lead (he was over 50), nevertheless is a commanding presence on screen. The sequence where he elicits the truth from Beery is alone worth the price of admission. The title refers to what happened to Beery "behind the door."

Although the movie has clearly deteriorated in spots, the restoration for the most part is crisp. The few inserted stills do not interfere or detract in any way. At seventy minutes, the film moves briskly without any slow spots. The photography is excellent.