Here's the introduction used in "Black Mask" for this short story when it was first published in 1924: "Like all of Mr. Hammett's detective stories, this tale starts with a very ordinary police case, and just as you think you have it all figured out, it takes several unexpected turns and ends up with a bang." But it's up to you to find out how the title fits the story. Neither "Black Mask" nor "The Big Book of the Continental Op" provides another clue. Librarian's note #1: this entry is for the story, "One Hour." Entries for collections of short stories, and each of the other individual stories, can be found elsewhere on Goodreads. There are a total of 28 short stories plus one incomplete; they can all be found by searching Goodreads for: "a Continental Op Short Story." Librarian's note #2: there are also two Continental Op novels, "Red Harvest" (also known as "The Cleansing of Poisonville), and "The Dain Curse."