Her name is barely known in Britain, but a Scottish teacher has become a publishing phenomenon in China, where her debut novel for young adults has sold more than 1m copies over the past two years.

Now Claire McFall, 35, from the Scottish Borders, is likely to become better known closer to home. Hollywood producers have snapped up the rights to her book for two major feature films – one version for English-language audiences and another for Chinese ones – prompting her to give up the day job.

She told the Guardian she was “blown away” after learning that Legendary Entertainment, maker of blockbusters including Godzilla, had acquired the worldwide film and graphic novel rights to her “Ferryman” trilogy.

McFall was at Peebles high school, where she teaches English part-time, when she took a call from her agent. “I did a bit of dancing round the classroom,” she said.

Her first book, Ferryman, is a modern retelling of the ancient Greek myth of Charon, the ferryman of Hades who transported souls to the underworld.

In her story, a young girl called Dylan emerges unscathed from the debris of a horrific train crash in Scotland – only to learn she is the only fatality: “The bleak landscape around her isn’t Scotland. It’s a wasteland haunted by wraiths searching for human souls. And the stranger waiting for her isn’t an ordinary boy. Tristan is a Ferryman, tasked with transporting her soul safely to the afterlife, a journey he’s made a thousand times before. Except this time, something’s different.”

Published in the UK in 2013, Ferryman won that year’s Scottish children’s book award for the 12-16 category and was shortlisted for various prizes, including the Carnegie medal.

The Guardian described it as “a touching, often funny and sometimes harrowing first novel about first love set in the mythologically and philosophically fruitful territory between life and death”.

McFall has received recognition in the Scottish press, but it is in China where she is a star. Since its publication there in June 2015, Ferryman has remained in the Chinese top 10 bestselling general fiction charts ever since, joined by her sequel, Trespassers, after its publication last September.

She is now working on the third novel, due next year. Ben Illis, her literary agent, said that to have two simultaneous top 10 rankings in any country was “astonishing”.

Visiting China with her last year was like Beatlemania, he recalled. Huge queues formed for book signings and one teenager fainted over the excitement.

The one thing missing has been the rest of the world taking note, he said. “It is hard to put into words how excited I am that Ferryman is to be adapted for the big screen by a studio I admire as much as Legendary, whose movies like Godzilla and Pacific Rim pretty much define modern blockbuster movie entertainment.”

Productions made by Legendary, which has a Chinese studio, have taken more than £10bn at the box office worldwide.

Illis is all the more excited because McFall was the first author he signed. “I thought she had such a skill with voice and character,” he said.

Like some of the most successful authors, McFall initially struggled. She recalls receiving dozens of agents’ rejection letters, but never considered giving up: “It was like a hobby. Some people do jigsaws – I was writing books.”

When Ferryman was released in China, she was excited to see it translated into another language but never expected it to sell more than a few copies. She said its success was “really humbling”. McFall’s mother used to be an English teacher, and her father worked in security. She is married to an archaeologist, Dr Christopher Bowles.

Her publishing success will now enable her to write full-time and look after their three-year-old son. Her fictional protagonist, Dylan, is aged about 15, and Tristan is a year or two older, she said.

While casting is yet to begin, McFall has some thoughts on it. “When I was writing them, I had people in my head, although tragically it was me in the girl part. Who doesn’t want to be the hero of their own story? Tristan was circa-Leonardo DiCaprio.”