Davie's life has lost all momentum, and being good-looking in a geeky, David Tennant way brings him no consolation.

He's only holding on to his job at the Virgin Megastore on Edinburgh's Princes Street (now closed, so no legal issues there, hopefully) by the skin of his teeth. We soon find out he's been in therapy and has problems with anxiety, practising mental relaxation exercises at stressful moments.

At the root of his problems is the death of his younger brother, for which he feels partially responsible. The tragedy broke up his family, sending his father into the arms of a younger woman and his mother to Australia. When we first meet Davie, he is buying the last of the Harry Potter books so he can read it aloud at his brother's graveside and let the boy know how the saga ends.

It's then that a homeless man gives Davie a magical MP3 player which plays people exactly the right song they need to hear at that moment: a song that reminds them of happier times, a song that will help them come to terms with whatever's troubling them. Davie has no control over it. The player (he nicknames it Jamesy) vibrates in his pocket and flashes instructions across its screen when it wants to be used. So Davie does have a role in life, after all. He's the Trackman, bringing solace to the needy. He can only describe it in terms of becoming a superhero. But, being young and troubled, Davie allows this new development to cause his life to spiral even further out of control.

In her debut novel, Catriona Child has all the makings of a cult hit. While it's mostly told in Davie's voice, frequent intrusions from an omniscient narrator ramp up the sense of dread as we discover more and more about his past. She handles the tension between the fantastical premise and the raw and sensitive matter of a dead schoolboy tastefully, and the book's sense of place makes it a delight for lovers of Edinburgh: there's even a Google Maps page where curious readers can zoom in on some of the featured locations.

TRACKMAN

Catriona Child

Luath Press, £9.99