AAZIM is 15 and hiding out in Hungerhill Allotments so he won't be deported with the rest of his family.

Nadimah's a bit younger and needs to leave the house where she is living as little more than a slave – and where things are about to get much worse.

As their situations become desperate, they set out together across Nottingham and the East Midlands, trying to find little more than safety and shelter.

Around that plot Nottingham-based author David Belbin tells a story for teenagers that aims to give an idea of the perils and struggles faced by asylum seekers and refugees in Britain.

The book is aimed at "reluctant readers" – teenagers with a reading level below the average who often don't pick up books at all. To write for them, you come up with a plot that a 13 or 14-year-old will find interesting but that's also understandable to someone with a reading age of seven or eight.

To write that way, David explained, you keep the book short. You write a linear plot with one point of view. If you introduce comparatively challenging words, you use them a few times to get the reader used to them. "The reader is having enough trouble decoding what the letters mean without giving them anything beyond that," he said.

What you do not do – what David never does – is talk down to the reader. Some reluctant readers are dyslexic. Some don't speak English as a first language. There are any number of reasons that a young reader can be labelled "reluctant".

But two possible assumptions are simply not correct. "We're not talking about lazy kids," David said. "And we're certainly not talking about stupid kids."

David has, over several decades, become a popular writer of young-adult fiction.

Most of his books are not aimed at reluctant readers but they are typically aimed at teenage readers.

The real problems and emotions of teenage life are what David tries to tap into with much of his writing. He writes about actual situations young people face. That puts him against trends in a genre that at the moment is all about pubescent wizards and hormonally-charged vampires.

"Social realism isn't doing well at all," he said. "But fantasy has never been my thing."

If social realism isn't doing well, David's writing is. He recently published a novel for adults, Bone & Cane, and its strong sales ensure that in future he'll be doing more writing for adults as well as teenagers. But books like Secret Gardens remain an important part of what he does. For Secret Gardens, he brought in an old friend, illustrator John Stuart Clark – better known as Brick.

David and Brick have known each other for years. They met 30 years ago when David walked by Brick's house and saw a sign reading "Cartoonist for hire". David, working for a housing association at the time, gave him a £30 commission for something about a "loan shark".

Brick didn't need much convincing to get involved in that project. He cares about asylum seeker rights and about giving reluctant young readers something they can get into. As an illustrator, he feels part of that tradition.

"When we were young, we didn't have that whole 'reluctant reader' thing," Brick said. "We had comics."

David and Brick both stress that, while the book offers a glimpse into the perspective of a young refugee or asylum seeker, it's not simply an educational book. "I'm not trying to write a right-on book that will only be used by left-wing teachers," said David, who recently became patron of the Welcome Project, a Nottingham-based charity that promotes refugee integration.

Before anything else, it's got to be a good story. Brick reckons a story of two teenagers on the run speaks to other teenagers in a specific way.

"I think the beauty of the story," he said, "is that it taps in with those feelings of getting away."

Secret Gardens, published by Five Leaves Press, is available now on Amazon.co.uk.