The Glasgow-based writer, whose works have included The Day I Swapped My Dad For Two Goldfish and Titus, and the pair behind The Infamous Brothers Davenport, The Not-So Fatal Death Of Grandpa Fredo and Slick had wanted to work with each other for some time, so this new idea seemed a golden opportunity for them all.
For Emanuel, Edmunds and Harrison's brief sounded particularly enticing. "They said, 'We want to do something about a 12-year old boy who is grieving for his mother'," Emanuel says of that initial conversation. "'Oh, and we want there to be a dragon. And we want it to be done without words.'"
Three years on, the end result of that conversation is Dragon, a collaboration between Vox Motus, the National Theatre Of Scotland and Chinese company The Tianjin People's Art Theatre, which opens at the Citizens Theatre, Glasgow, this week before touring the country.
Dragon tells the story of Tommy, whose mother died a year earlier. Tommy's dad is racked with grief, his big sister will not talk to him, and he has become the target of the school bully. When Tommy opens his curtains one day, he discovers a dragon with whom he finds an angry affinity. Tommy and the dragon do everything together, but when fires start happening around Glasgow, things change in a story that has a very personal root for its author.
"I came to Scotland a year after my own mother passed away," Emanuel explains. "I have written about grief in a lot of different ways, and been quite open about my own grieving, and this seemed to fit in with that. Having said that, I think it is only autobiographical in the sense that everything you write is autobiographical.
"I did lose my mum, and I do have a father and a sister, but I am not the play's main character. None of what happens in the play happened to me, and a dragon did not come to my house. But when you are grieving you do not always have the words for how you are feeling. Tommy can't speak, and he does not know how to express himself. Out of that I wanted to find a new form, because there are not that many plays with no words."
If Tommy's relationship with the dragon sounds akin to that between the little boy and his stuffed toy tiger in comic strip Calvin And Hobbes, albeit with inclinations for fire-raising, think again. Nor is the dragon an invisible friend for Tommy.
"Tommy can see the dragon, and nobody else can," Emanuel explains, "but it's certainly not an imaginary dragon. When the Chinese company got involved, that really changed the dynamic and opened the story out, because when we think of dragons, you have something like St George, who slayed a dragon, but the Chinese believe that there is a dragon in everyone, and that is about balance and equilibrium. So there is this idea that we all have our own dragon, and we all have our own things to deal with, just as Tommy does."
Vox Motus's pedigree utilising puppets, magic and other visual effects in their work was certainly a gift for Emanuel, who describes his script for Dragon as "a cross between a short story and a film script, with myself as a kind of story wizard".
"Historically," he says, "you can look back at Bertolt Brecht, who said his work should always be understandable, and there is a lot of visual stuff going on with the Berliner Ensemble. I saw them in Berlin, and I don't speak German, but I could understand what was going on. Then you have got something like (animated feature film) The Artist, so with Dragon it is a case of me wanting to try things out. Titus was just one man on stage telling a story for 45 minutes, but I am not interested in repeating myself, and never want to do the same thing twice, so this is the complete opposite of that."
While not specifically aimed at children, Dragon's exploration of childhood is something Emanuel knows well.
"I have done quite a lot of work for young people," he says, "and although Vox Motus have done a lot of work for adults, they noticed their audiences were getting younger, so began to be interested in pursuing the younger end of that spectrum. I think Scotland has proved again and again that theatre for young people can be made with real depth, even though writing for children is much harder than for adults, because they won't put up with just any old rubbish."
In describing who Dragon is for, Emanuel contrasts his show with another NTS piece, the stage adaptation of John Ajvide Lindqvist's romantic horror novel previously adapted for film as Let The Right One In.
"Let The Right One In was an adult show about childhood," Emanuel says. "Dragon is a show about childhood as well, but it is for both children of about 12-upwards and adults, and I think people will have very different experiences of the show. I am really interested in everyone having their own different dragon experiences, and what the dragon means to them.
"I have a personal wish to explore the idea that children experience things differently to adults, and what it is like to feel a particular emotion for the first time, whether it is grief or first love. There have been recent suggestions that children do not feel grief, and that they can just get on with things, but that is not my experience at all.
"Of course children feel things, and that is what Dragon is about. I have always been interested in telling big emotional stories, and there is something really eloquent in doing it without words. It can speak more powerfully done that way. There is a real poetry in silence."