THE Day I Swapped My Dad For Two Goldfish is one of those titles that strikes straight to the heart of our recklessly naughty side, whatever age we are.

And that, according to writer Oliver Emanuel and director Lu Kemp, is a very good reason for making Neil Gaiman's children's story into a stage play.

Happily the National Theatre for Scotland (NTS) was thinking along similar lines. Unlike an earlier NTS production, Wolves in the Walls, Gaiman didn't adapt his own book so Kemp and Emanuel got to grips with Goldfish (as it's briskly referred to in conversations) and from now until the end of May an interactive promenade production – for ages six to 10, but with a family-friendly attitude – will tour to various venues around Scotland.

For those of you who haven't come across the Gaiman tale (with illustrations by Dave McKean), here's a very reduced synopsis. Young boy is so smitten by best friend's goldfish that despite little sister's awful warnings he swaps – you've got it – the fish for his own dad.

Mum, understandably, is not impressed but retrieving Dad is far from straightforward as he's become the currency of many subsequent trade-offs.

"It's a great 'what-happens-next' adventure," says Kemp. "But even when it seems hilariously fantastical, it still feels very real because of the relationship between the brother, whom we've called Neil, and his little sister."

In the play, that little sister apparently owes as much to Emanuel's own childhood memories as it does to Gaiman's characterisation.

"The boy, Neil, thinks he's really very clever but his Little Sister – we've called her that because it's how he thinks of her – isn't at all convinced. And that really struck a chord with me. Because I'd have these great ideas, think I was really smart – and my little sister would bring me back down to earth with a bump. She still does, actually.

"So I knew how that relationship felt. And I knew a lot of our audience, adults as well as children, would identify with it as well."

But even if there are strands of "what's right, what's wrong and what's truly a good idea" woven into the action, both Kemp and Emanuel are clear in their own minds that the production has to feel like a really intriguing adventure. And to help draw us into the frame, as it were, of the Gaiman/McKean story, this Goldfish will unfold as a promenade from space to space.

"It's been really exciting for us to plan this out, and make it work across different venues," says Kemp. "We're opening at the Beacon, a brand new space that's recently opened in Greenock, and there we're going through all the backstage spaces the public don't usually get to see.

"So the whole idea of inviting young audiences, family audiences, to explore theatre works on really different levels: they have an adventure with Neil and the other characters, and they discover what lies behind so many closed doors at the Beacon."

Clearly neither of them would swap what they're doing, but in childhood? Kemp admits to hankering after a pet dragon, even now.

Emanuel craved "a really good bike". "I always had second-hand, not-very-good bikes. I still don't have the ideal bike – but I've still got my Dad. He's a really good guy and I'm glad he's still around."

Gaiman, it seems, always wanted a really convincing gorilla mask.

And the roots of this story? Well once upon a time, his son stomped off to bed saying: "I wish I didn't have a dad. I wish, I wish ... I had goldfish!"

And the rest is now a new NTS production.

The Day I Swapped My Dad For Two Goldfish is at Beacon Arts Centre, Greenock, today until Saturday.

Details of times and touring at