I've never been to a funeral for a soft toy before. Nor, come to that, even witnessed one. But there’s a first time for everything, for in the opening scene of this musical, we find nine-year-old Dani singing a requiem to one of her favourite cuddly toys.

It soon becomes obvious that Dani has a Guardian Angel, who encourages her to stay positive and enter a world of imagination to escape the horrors of her reality. For Dani has leukaemia, and has lost all of her beautiful curly long hair. Her hospital room-mate, Marty, has also learned to avoid the reality of his own illness, living his life through the world of superheroes and movies. He's right: you never see Superman afraid – or worse still, dying.

The musical score is a strong one. The songs are uplifting, and there are some delightful moments to savour throughout. My favourite, perhaps, is Trivial Pursuit of Death, a hilarious spin on the rather dry and dated board game where every question cleverly produces the same answer.

Natalie Hatcher is totally convincing as the spirited and feisty Dani, without being excessively sentimental. Rob James commands the stage in assorted roles, both as the watchful Guardian and the deadly disease in various guises. Even Darth Cancer gets a cameo part!

I loved watching the developing relationship between the two young characters too. Conner Gillooly captured Marty’s balance of vulnerability and bravado perfectly. Alongside all this, Dani's mother (Cynthia Dougherty) struggles with the whole situation; her grief is so tangible, her pain so real. She portrays the total suffering of a mother who is helpless – what feeling could possibly be greater than the illness of your child, and the desire to change places and take their pain away?

At times, the limited set and out-there concepts required some serious suspension of disbelief. We accompany Dani and Marty exploring one of her soft toys’ ovaries, and then they visit Heaven to speak to God and get some questions answered for themselves. These scenes sit a little oddly with the rest of the show, but they’ve built up enough goodwill by then that I was ready to follow along with them.

“There's nothing cool about cancer,” Dani exclaims at the beginning. And of course she’s right, but this musical might just be the closest thing. Watchable, accessible, funny and touching, all the ingredients were there. It’s not depressing, but come prepared with your tissues, for there is no escaping just how moving this story is.