Brilliant staging — as in “Harry Potter” or “Hadestown,” another mythological mash-up — might have made up for that. But “The Lightning Thief” is stranded in the contradictions of its ambition. Effects that might have looked crafty and imaginative in the original production look cheesy and anticlimactic in this one. Lee Savage’s set consists mostly of marbleized plywood scaffolding; the band, sitting atop that scaffolding, numbers just five. And why is Zeus’s lightning bolt, when it finally appears, about as awesome as a fluorescent Shake Weight?

It’s symptomatic of the illogical workarounds that the scene in which Percy’s supernatural powers are first manifested at Camp Half-Blood — a scene that, in the book, involves an exploding toilet — must make do with toilet paper instead, as if he weren’t the son of Poseidon but Charmin.

Perhaps at this point I should take off my Scrooge glasses and see the show as a family might — albeit a family paying as much as $199 per ticket. A child might in fact enjoy the fusillade of toilet paper. Parents might enjoy McCarrell’s mostly laid back, tossed-off performance; underplaying is definitely the way to stand out in this production. And everyone might root for the cast of unknowns, all but McCarrell making Broadway debuts. It’s true that they give it their overamplified all.

But — glasses back on — I have to ask: What do we want musicals for young people and their families to be? Serious and urgent like “Dear Evan Hansen”? Sure, though that show is too exceptional to serve as a viable model. Moral tales sugared with spectacle like anything Disney? I can live with that. (Well, maybe not “Tarzan.”)

It’s the musicals lost somewhere in between I find myself unable to countenance. Not only are they often about whiny teenagers; they seem to be written by them as well .

Shows of this ilk — not just “The Lightning Thief” but also “Be More Chill,” “School of Rock” and, despite its terrific score, “13” — normalize the idea that actually quite privileged youngsters are victims of social or parental neglect. They bellow their rebellion in catchy songs; they go on childish quests to claim their maturity.

“The Lightning Thief” doubles down on that agenda . Its finale, an anthem called “Bring On the Monsters,” would be laughably banal if it weren’t so aggressively false. “The battle’s just begun!” the characters instruct the audience.

What battle? The one with the parents who ponied up the big bucks to bring you to a show featuring flashlights and sock puppets? Better to count your blessings and find another fantasy.

The Lightning Thief: The Percy Jackson Musical

Tickets Through Jan. 5, 2020 at the Longacre Theater, Manhattan; 212-239-6200, lightningthiefmusical.com. Running time: 2 hours 15 minutes .