Nico Muhly is a composer who has everything. At 32, he’s a well-known figure in the classical music world. He’s released a range of recordings, including everything from shimmering choral music to pop-style albums, and a broad range of work demonstrating that he has something to say. And one of his two operas to date, “Two Boys,” opened at the Metropolitan Opera on Monday night, to tremendous excitement: half the music world, it seemed, turned out to see it.

Paul Appleby as Brian in Nico Muhly's "Two Boys,” an opera about the perils of the Internet, which opened at the Metropolitan Opera on Monday night. (Micaela Rossato/Metropolitan Opera)

Everybody involved clearly worked hard to do everything right. Craig Lucas wrote a viable dramatic libretto, a kind of whodunnit (a 13-year-old boy is stabbed, evidently by a 16-year-old boy, and a middle-aged female police detective tries to figure out what happened). Muhly wrote vivid choral music, plunged into the sounds and colors of the orchestra with a will, sprinkled his score with driving neo-Minimalist rhythms and tiny snatches of neo-Romantic lyricism, set the text so it could sometimes be understood, and even revised and tweaked the opera after its first run at the English National Opera in 2011. Bartlett Sher created a thoroughly professional production, with jagged choreography (by Hofesh Shechter) and whirling animations (by 59 Productions) across Michael Yeargan’s dark, opera-noir sets. And the Met gave it an impressive cast, led by the excellent conductor David Robertson in the pit. If great opera could be produced from a recipe, this one would have been a masterpiece. But all these components did not combine into something with a real, beating heart -- or even any characters you cared about.

Heavy-handed: Alice Coote as Anne Strawson, Jennifer Zetlan as Rebecca, and Paul Appleby as Brian in Nico Muhly’s “Two Boys” at the Metropolitan Opera. (Ken Howard/Metropolitan Opera)

Of course, there plenty of operas about the past that don’t feel dated -- because their characters come to life. But this is more than “Two Boys” could pull off. One could sympathize with Brian (Paul Appleby), the 16-year-old who gets caught up with what appears to be a life-or-death, increasingly convoluted on-line melodrama; but the figure remained somewhat generic. As for Anne Strawson, the detective (Alice Coote), I believe the creators may genuinely have thought that they were creating a poignant portrait of a lonely and confused woman, but what they gave us, despite Coote’s spectacular singing, was a bad, badly dated, and profoundly unlikeable stereotype.

And most of the rest of the characters -- Rebecca, the girl Brian meets in the chat room (Jennifer Zetlan); Jake, her hunky brother (Christopher Bolduc); Fiona, their mother’s friend and a secret agent (Sandra Piques Eddy), and the sinister gardener/killer Peter (Keith Miller) -- turn out to be inventions of the 13-year-old victim, the real Jake. Jake -- impressively played by the boy soprano Andrew Pulver, who held his own with the other singers -- creates a host of chat-room identities to help him get, and hold, Brian’s attention. So though uniformly well sung, these figures were all deliberately two-dimensional.

I hasten to add that conventional depth of character does not have to be a prerequisite for opera, if you change the rules and establish new definitions for what you’re trying to do: Philip Glass’s “Einstein on the Beach” is a case in point. But “Two Boys” is explicitly setting out to be grand opera -- something it signaled from the opening moments, when Appleby’s Brian ran on stage and sang “My friend has been stabbed!” in a traditional operatic voice, in a familiar contemporary-opera, not-quite-arching-melody, hyperdramatic idiom. It was a signal -- perhaps inadvertent -- that the opera was going to be a kind of thing we’d heard before, and a little bit of the air went out of the evening at that moment.

Paul Appleby as Brian and Sandra Piques Eddy as Fiona in Nico Muhly's "Two Boys." (Ken Howard/Metropolitan Opera)

But the idea didn’t develop significantly, musically or dramatically or visually, beyond the first chorus, apart from the addition of elements illustrating the treacherous terrain online: Brian stumbles across a gay sex scene, adding to his mounting sense of dread and titillation and uncertainty. I don’t think Muhly quite meant to signal “Internet bad!” in such broad terms, but for all of the inventiveness of his initial idea, the opera is oddly straitlaced and old-fashioned in its depiction of online life.

Indeed, one of the great puzzlements of “Two Boys” was its lack of sophistication. The libretto gives a nod to everyone’s point of view, even the clueless parents (Maria Zifchak particularly strong as Brian’s mother, Kyle Pfortmiller as his father, and Caitlyn Lynch melodious as Jake’s spacy mother), and it also included plenty of sex scenes, more and less explicit, that will no doubt occasion much tut-tutting, in the best operatic tradition (“Carmen,” too, was thought scandalous in its day). But rather than playing inventively with the shifting identities and fictions and suspensions of disbelief that are part and parcel of internet interaction, and key to this particular plot, the opera was heavy-handed, even obvious, down to the way Sher had each character march forward, and plant her feet, and sing. Sex doesn’t equal sophistication any more than a tight libretto and dramatic honing equal an effective opera. I think Muhly has a good opera or several in him, down the road, but “Two Boys” isn’t it.

“Two Boys” continues through November 14th at the Metropolitan Opera.