On a spring morning in London, a wealthy widow visits a funeral parlor and makes arrangements for her own funeral. She then lunches with a friend, attends a theater board meeting and returns home, where she is strangled with a red curtain cord.

The bizarre murder of Diana Cowper sounds like a case for Holmes and Watson. Alas, they’re not available, being fictional characters. So how about Hawthorne and Horowitz? Wait, they’re fictional, too. Aren’t they?

Anthony Horowitz, you may remember, out-Christied Agatha Christie in last year’s “Magpie Murders,’’ his clever take on the traditional detective novel. Now he’s up to some new tricks in “The Word Is Murder,’’ another entertaining puzzler full of red herrings and dead ends. But this meta-mystery is narrated by a writer named Anthony Horowitz, who is writing a book about ex-police detective Daniel Hawthorne, called in as a consultant on the Cowper case.

It’s not nearly as confusing as you might think because if anyone is qualified to cast himself as a modern-day Watson, it’s Horowitz. His extensive credits include teleplays for “Midsomer Murders’’ and “Foyle’s War,’’ and he has paid homage to Holmes in his novels “The House of Silk” and “Moriarty.” And if you’ve forgotten that he also is the author of the Alex Rider thrillers for kids, Anthony Horowitz the character reminds you at various turns in this book. The mix of fact and fiction is mostly gossipy fun — as in a meeting with filmmakers Stephen Spielberg and Peter Jackson about a “Tintin” sequel — but also is a tad tiresome as Horowitz tries to figure out the eccentric, taciturn Hawthorne while Hawthorne figures out who killed the widow Cowper.

The unlikely pair crisscross London by Tube, interviewing witnesses and following leads. They visit the seaside town where the dead woman was involved in a hit-and-run case 10 years ago and where a hotel manager introduces herself as Mrs. Rendell, “like the crime writer.” Diana Cowper also was the mother of well-known actor Damien Cowper, who flies in from Hollywood for the funeral, which is followed by another grisly murder.

A seemingly brilliant investigator, Hawthorne reveals little about himself and berates the often baffled Horowitz for asking questions. Horowitz wonders how he’s going to write a book about an unsympathetic, secretive detective he doesn’t like very much. “The world has had quite enough of white, middle-aged, grumpy detectives.’’

But don’t take Horowitz at his word. “The Word Is Murder’’ is just the first book in a projected series.

Nancy Pate is a writer and reviewer in Orlando, Fla., where she loves to read crime fiction and has even written some.

The Word is Murder
By: Anthony Horowitz.
Publisher: Harper, 390 pages, $27.99.