Sherlock Holmes in Washington is another entry in the series set during World War II and most of it is set in the United States. The propaganda isn't as heavy handed as in the other war based films of the series, Rathbone sports a singular hairstyle, and Bruce has some good moments enjoying the American culture. Look out for an interesting aerial shot of New York showing only a few modest skyscrapers, and also one of the best scenes of the series where top-secret microfilm gets passed unknowingly from person to person at a party.

Synopsis

The film opens with John Grayson, aka Alfred Pettibone, boarding a plane bound for Washington DC. Pettibone takes his seat aboard the small aircraft, squeezed in among the passengers who include a fair few suspicious characters in their ranks. After landing in Washington, the passengers are taken by train into the city centre.

When aboard the train, Pettibone soon realises that he's in danger. He deliberately talks to various passengers before passing the microfilm to a young lady who needs her cigarette lit. Soon after, the carriage lights go out and Pettibone is abducted by the small coterie of criminals shadowing him.

Back in London, Sherlock Holmes receives a visit from Mr. Ahrens who tells him that John Grayson is in fact Alfred Pettibone travelling under an alias. Pettibone is taking some very important state documents to the United States but he has disappeared somewhere on route. Holmes agrees to take on such an important case and decides to visit Pettibone's home before flying to Washington to investigate.

At Pettibone's house, Holmes and Dr. Watson find copying equipment and some match folders; Holmes deduces that Pettibone was carrying the document in the form of microfilm, hidden in a 'V for Victory' match folder. When Holmes and Watson are leaving the house, Holmes narrowly averts their deaths when he spots a large piece of stonework just in the nick of time, launched from the roof above.

Holmes and Watson board the flight to Washington, where Watson takes the opportunity to swot up on some American vernacular of the day. They're met at the airport by Detective Lieutenant Grogan and Mr. Lang, who drive them to a hotel stipulated in an anonymous note Holmes had received earlier. At the hotel, Holmes receives a grisly package; Alfred Pettibone's corpse wrapped in a blanket and crammed into his own packing case, along with a note warning Holmes to stop his investigation.

Holmes leaves the blanket in the hands of the FBI laboratory before leaving with Watson to inspect the train carriage that Pettibone was abducted from. Somebody has beaten them to it and has ransacked the carriage but Holmes manages to glean clues from the attendant; Pettibone had lit a young woman's cigarette with the match folder, and she is soon to be married to a naval officer.

The criminal's leader discovers who the young woman is, and her whereabouts, so he sends his men to find her and the microfilm. At their hotel, Holmes scours the society pages in the local newspapers and Watson enjoys a milkshake while reading the sports section. Holmes finds the clue he needs and now knows that the woman Pettibone had passed the microfilm to is Nancy Partridge, who's aunt is throwing her a party to celebrate her engagement to Lieutenant Pete Merriam.

In a great scene at the party, the match folder with the microfilm is unknowingly passed from hand to hand among the guests but it eventually finds its way back into Nancy's handbag. Lt. Merriam is called upstairs to answer a bogus 'phone call, and when he doesn't return, Nancy goes to investigate but ends up rolled up in a large carpet. Yes, you read that right, rolled up in a carpet. She's then abducted by the criminal gang posing as removal men and taken to their headquarters.

Holmes and Watson go to the apartment block where the party was held, where they're met by Lt. Grogan. In Nancy's apartment, they find an unconscious Lt. Merriam, and Holmes finds clues that tell him Nancy has been abducted by the bogus workmen, concealed in the rolls of the large carpet. Holmes and Watson return to their hotel where Holmes examines the blanket that Pettibone was wrapped in. He deduces that it came from an antiques shop, so he and Watson start on their search of the all the antiques shops in Washington.

Holmes and Watson find the shop after a city-wide hunt, so Holmes goes in posing as an eccentric art collector whilst Watson waits outside for the signal to fetch Lt. Grogan. In the basement of the shop, Nancy is being interrogated by Richard Stanley, leader of the gang, when he unknowingly lights his cigarette with the V for Victory match folder. Upstairs, Holmes makes enough of a raucous to warrant Stanley's attention, so he signals Watson before going to meet Stanley. Stanley is a former WWI spy called Heinrich Hinkel, he's had his name changed and now poses as an antiques dealer but in actuality, he sells state secrets.

Holmes holds Stanley at gunpoint but after some argy-bargy with the gang, Holmes is tied up with Nancy. Watson and Lt. Grogan arrive with more men, just in time to save Holmes and Nancy but they're unable to prevent Stanley from escaping. Holmes races to the office of Senator Babcock, who spoke at length to Pettibone on the train, because Stanley presumes Babcock must have the microfilm as he couldn't find it on Nancy.

Holmes gets to Senator Babcock's office first but Stanley walks in with a gun, demanding the microfilm. As he does so, Lt. Grogan arrives, sneaks up on Stanley and arrests him without incident. Holmes takes great pleasure in pointing out that Stanley had held the microfilm in his own hands earlier that day.

The film closes with Holmes lauding the United Sates and its democracy, quoting Winston Churchill as some fittingly patriotic music stirs in the background.