In the DC Universe, Batman is generally considered to be the greatest detective (though some recent writers—and film directors--seem to occasionally forget that.) But, in the Silver Age DC Universe at the very least, there was one man who was an even greater detective. Batman himself acknowledges this within the pages of this issue, so there’s no sense in arguing about it.
To celebrate the occasion, the double-sized issue featured a multi-chapter story involving Batman and several other detective characters from the DC Universe. We start with Slam Bradley, a hard-boiled P.I. character who appeared in Detective Comics #1, brought back now after a long absence. Older but still tough, he becomes involved in a kidnapping case that turns out to involve several descendents of Sherlock Holmes’ arch-nemesis, Professor Moriarty. He gets an assist from the Dynamic Duo along the way.
This leads us smoothly into a flashback that gives us the details of that lost case, where Holmes and Watson foil a plot by Moriarty to assassinate Queen Victoria.
The climax involves Batman getting a bit of help from a certain famous detective--now very old but still the best there is.
The whole story is very well-done. The plot moves along briskly, with plenty of action, but with each of the characters given a chance to show their respective skills as detectives. (The Holmes flashback is more action-oriented than the majority of the original Conan Doyle stories, but Holmes still shows off his powers of deduction and the addition of more action is appropriate to the comic book format.)
A different artist drew each chapter, something that has been distracting in other comics. But here, each chapter is sufficiently self-contained to make the different artistic styles work effectively in terms of drama and the overall flow of the story.