What it's about: "London: -- it's like a great cesspool into which all kinds of criminals ... are irresistibly drained. And sometimes it's not a question of 'who' but a question of 'who knows ...' " Would you be surprised to learn that the great detective making this abstruse observation Sunday night is none other than Sherlock Holmes (Benedict Cumberbatch)?

Of course you wouldn't. As all know, Holmes faked his own death at the conclusion of the second season ("The Reichenbach Fall," when he apparently fatally plunged off a hospital roof). What we don't know is how he did this, and why poor, bereft Dr. John Watson (Martin Freeman) had to witness the whole bloody thing. Answers, or some, are forthcoming Sunday. (And why is Holmes rambling on about cesspools anyway? Watch ...)

My say: The fuss is justified. Sunday's return of the Steven Moffat and Mark Gatiss-created series is a triumphant one, and should easily establish "Sherlock" among TV's finest series.

The episode, title "The Empty Hearse," refers to a blog created by one Philip Anderson (Jonathan Aris), a New Scotland Yard forensics specialist (from Season 1), who has gone somewhat barmy as he pursues various theories about how Sherlock not only survived his fall but faked it as well. Few believe Anderson -- including Watson, who's just trying to move on from the "tragedy" -- but his obsession forms the puckish conceit that threads the entire episode. How did Holmes "kill" Holmes? Well ...?

Written by Gatiss, "Hearse" is a brilliant flight of farcical lunacy -- a hall of mirrors designed to confound not only befuddled Watson and Anderson, but you. Nothing is meant to be as it seems, and when it is, then you'd better take another look.

Most unexpectedly, "The Empty Hearse" is funny, occasionally hilarious. (Gatiss is a charter member of the British comedy group The League of Gentlemen.) Everything Sunday night is primed to make viewers laugh, then think, then do a double-take -- and do it all over again. With a pair of world-class actors as your guides, you most assuredly will.

Bottom line: Easily the best hour and 27 minutes of television I've seen since Sept. 29, when "Breaking Bad" ended.

What: "Masterpiece Mystery: Sherlock, Series III: The Empty Hearse"

When: 8:58 p.m. Sunday

Where: TPT2