After a break of more than five years between novels, John Green is enjoying a positive reception for new book "Turtles All the Way Down."

The set-in-Indianapolis novel is riding a three-week streak at No. 1 on The New York Times Best Sellers list for young adult hardcover books. Green and his brother, Hank, traveled coast to coast in October to promote "Turtles" with songs, comedy and serious talk about the story's focus on mental illness. And Amazon.com selected "Turtles All the Way Down" as the best young adult book of 2017.

But "Turtles" isn't the story Green started writing following the blockbuster success of 2011 novel "The Fault in Our Stars."

The author told IndyStar about two stories — one about teenage con artists, the other based on an online detective agency run by teenagers — he worked on and eventually abandoned.

Green read an excerpt of the con-artist story during a 2013 Butler University hunger-relief benefit titled "Writers' Harvest."

The passage described a rain-umbrella scam executed at restaurants near Monument Circle.

During an Oct. 19 interview before the "Turtles" book tour played Pike Performing Arts Center, Green said he wrote 30,000 words of a story he called "The Racket."

“I love the idea of a teenage con artist story,” Green said. “I love noir mysteries that take place in high schools.”

"The Racket" stalled, however, when Green decided the story lacked emotional depth.

"It never clicked," he said. "I was trying to do something because I thought it was clever and not because it spoke to something, really."

'Turtles' tour:John and Hank Green balance anxiety and joy

'Stranger Things 2':A 53-song listener's guide for the sequel season

Concert recap:Lady Gaga shares a big night with Indiana ‘Monsters’

Green then explored the online detective agency idea. During a July 2015 interview as part of promotion of the film adaptation of Green's "Paper Towns" novel, Green said the follow-up to "The Fault in Our Stars" likely would center on social media and online interactions.

“Again, very high concept, very fun … (but) no guts in it, at least not of the kind I needed,” Green said at Pike.

Readers of "Turtles All the Way Down" can see traces of the detective-agency tale when protagonist Aza Holmes and her friend, Daisy Ramirez, search for information about a missing Indianapolis billionaire.

"I did save a little bit of that stuff, and I saved some of the vibe for when Daisy and Aza kind of go down the rabbit hole," Green said.

Ultimately, Green turned to his own struggles with obsessive-compulsive disorder and anxiety for the framework of "Turtles All the Way Down."

Aza's moment-to-moment existence is hindered by "thought spirals," something Green has described as affecting his own mental health.

Green said he's found effective treatment by taking prescribed medicine as directed, through cognitive behavior therapy and by ramping up physical activity.

“I guess I got to a point where I realized that the big story I knew something about was this story that was going to be hard for me to tell and was going to be kind of personal," he said. "But it was the story I had a way into.”

Call IndyStar reporter David Lindquist at (317) 444-6404. Follow him on Twitter: @317Lindquist.