Siobhan Dowd, who died of cancer in 2007 aged 47, dedicated her life to children’s rights and children’s writing. In her last three years, she completed a run of four novels for young adults that handled dark themes such as domestic abuse and terminal illness with great tenderness and compassion.

The final book she completed is the first to reach thebe stage;, and it could hardly find a more experienced or capable adaptor than Mike Kenny. Even so, the story – about a 14-year-old named Holly who runs away from her foster parents in a bid to locate her real mother in Ireland – makes for a far-from-simple transference, as the road trip occurs primarily within the landscape of Holly’s imagination.

Sarah Brigham’s fluid and fast-moving production subtly ensures that you never know quite where you are. On one level, it charts the geographical progress of a fugitive teenager evading police and social services in a stolen wig. On the other, it’s a psychological exploration of the alternate persona she assumes beneath the hairpiece, which masks her insecurities so completely she names it Solace.

Dark as the story becomes, there’s an uplifting element of fantasy that finds Holly/Solace thumbing lifts from curiously chivalrous bikers and a lovely bloke in open-toed sandals who introduces himself as the only vegan trucker in the service station. Above all, it makes a great vehicle for the former Shameless star Rebecca Ryan. It’s hard to think of an actor more capable of veering between the ages of 12 and 27 at any given moment; nor does she necessarily seek our affection, as Holly can be an absolute horror at times.

Dowd’s last act was to start a trust to improve literacy among children in care. Proceeds from this drama will go to support towards that, which is at least some form of solace.

• Until 14 March. Box office: 01332 593939. Venue: Derby theatre.