Ferrell, Reilly in a loony misfire

In the rare moments when the mystery spoof “Holmes & Watson” clicks, the movie is like a cross between a raunchy ’80s comedy and a Daffy Duck cartoon. As super-detective Sherlock Holmes, Will Ferrell is just like Daffy, the overconfident hero, blustering his way into trouble. And as Dr. John Watson, John C. Reilly is Porky Pig, the long-suffering sidekick. They’re a winning pair of losers.

But while Ferrell and Reilly’s Daffy and Porky routine is good for a few chuckles, it’s likely to disappoint fans of the more sidesplitting “numbskull buddies” dynamic the duo perfected in their hits “Talladega Nights” and “Step Brothers.” Even the stars sometimes look befuddled about what they’re supposed to be doing, romping around Victorian London in a parody that never figures out what it’s mocking.

Written and directed by Etan Cohen (who previously made the Ferrell vehicle “Get Hard”), “Holmes & Watson” starts with Arthur Conan Doyle’s master sleuth as a boy, learning to suppress his feelings so the bullies at school won’t get to him.

That odd prologue — not that funny, not that relevant to the plot — is the first big sign of trouble for “Holmes & Watson.” Cohen and Ferrell (who coproduced the picture) apparently wanted their Holmes to be as brilliant as Doyle’s, while still letting the star play to one of his strengths: acting like an overgrown child. Their solution? Make Holmes so emotionally stunted that he’s kind of a drip to be around.

Fast-forward to the early 1900s, and Sherlock Holmes and his best friend, Dr. Watson, are two of the most famous people in England, thanks to their long battle of wits with criminal genius professor James Moriarty. But then Moriarty escapes justice and threatens to kill the queen, putting the crime fighters’ reputation at risk.

Ralph Fiennes plays Moriarty, in one of the movie’s many impressively cast supporting turns. “Holmes & Watson” also has Kelly Macdonald as the landlady/servant Mrs. Hudson, Hugh Laurie as Sherlock’s brother, Mycroft, Rob Brydon as Inspector Lestrade, Steve Coogan as a shady onearmed tattoo artist and Rebecca Hall as a visiting American doctor who bewitches Watson.

Because of the talent involved, every now and then “Holmes & Watson” hits on something bizarrely inspired. But too many of the movie’s gags land with a thud. An extended dig at President Donald Trump comes off as smug. An Alan Menken-penned musical number is more clunky than magical. Multiple smutty scenes never build up any good scatological momentum because the picture’s rated PG-13.

“Holmes & Watson” is more of a well-meaning misfire than a total train wreck. It’s frustrating mainly because all of these folks can do much better.

GILES KEYTE/SONY PICTURES John C. Reilly, left, and Will Ferrell in “Holmes & Watson.”