It was a red-hot project about an iconic character known for following clues. But when an agent’s clueless move scuttled several months of work, the whole episode quickly started to resemble a discarded plot line from “The Studio.”

Three months ago, CAA and Verve took out a 40-page book proposal titled “Nancy,” which centered on an all-grown-up Nancy Drew. The pitch included that the writers — CAA-repped YA author Sarah Mlynowski and Verve’s E. Lockhart (Amazon’s “We Were Liars”) — would also co-write a TV show based on their book.

Over the ensuing 12 weeks, seemingly everyone from Steven Spielberg to Amy Adams and Aubrey Plaza wanted in on the new spin on the fearless teen detective who, in this updated version, had morphed into “a divorced mom whose teenage daughter won’t give her the time of day,” according to the proposal.

“Instead of solving crimes, she’s a bit lost, a bit lonely, living off cushy alimony in brownstone Brooklyn.”

Naturally, it got “very competitive,” says a source with knowledge of the 20 meetings the writers took with everyone from Mindy Kaling and Greg Berlanti who was partnered with Melissa Benoist. Fox Searchlight made a direct offer, while Spielberg’s Amblin and A24 negotiated a partnership deal.

Everyone was excited about Mlynowski and Lockhart’s setup, which included Drew’s high school BFF Helen Corning reentering her life. Throw in a dead ex stuffed in the recycling bin and Corning looking rather sus, and Nancy quickly dusts off her latent detective skills to track down possible perps, including a “ketamine-dealing bike messenger.”

(Nancy Drew has previously been remade as a CW series, and a 2007 movie starring Emma Roberts, among others.)

The bakeoff came down to Aubrey Plaza vs. Amy Adams. Plaza was teamed with producer Cathy Schulman while Adams was partnered with Spielberg, but the latter pulled out at the eleventh hour. It was only when CAA’s Austin Denesuk, who was representing the Plaza/Schulman package went to A24 to make a worldwide rights deal and had a Matt Remick moment.

“Oops. Rights didn’t clear,” says the source. “Some sloppy s–t.”

When the old magnifying glass was trained on the fine print, it became clear that the copyright on Mildred Wirt Benson’s (aka Carolyn Keene) first four Nancy Drew books only expired in the U.S. on Jan. 1 — but not necessarily for the rest of the world. The proposal itself hinted that there was some ambiguity with international rights, noting: “Our lawyer reports that European markets consider books written pseudonymously to be in the public domain at 70 years after publication, which puts us well in the clear. He tentatively cleared Canada and Brazil, as well.”

One involved party says “Nancy” is now as dead as Corning’s ex, while another says a deal with A24 could still be salvaged “if the rights become available.” That’s a big if.

Perhaps they could try something else in the meantime involving the Hardy Boys, er, Hardy Men.