Lewis and Rhona are on a residential trip to the Highlands with the rest of their class of eleven-year-olds from the East End of Glasgow. Lewis isn't having a great time - he's "rubbish at rugby, clueless at kayaking, a failure at football and ... abysmal at abseiling". He didn't even want to go, but his mum insisted. His best pal Rhona is making the most of the trip, but even she can't get Lewis to start enjoying things.
But then Lewis sees something. Something impossible. As he dangles from an abseiling rope, helpless and looking like "soap on a rope" (as Rhona so helpfully puts it) he sees a unicorn. Not a sparkly, rainbow-tailed unicorn like you'd see on a five-year-old's lunchbox, but "a huge dark beast, a heavily muscled horse with a gleaming, rippling black mane."
Before long, Lewis and Rhona discover that he's not hallucinating, not seeing a mirage, but unicorns are real, they live in the wilds of Scotland, and they're in terrible danger.
Guardians of the Wild Unicorns follows Lewis and Rhona as they try to save the magical beasts. It's a race against time as the end of the residential trip draws near, and the threat to the unicorns looms larger. Lewis and Rhona's friendship is tested, and they face adversity, adventure, and real danger.
This is a fast-paced adventure with a conservationist theme and a magical twist. It's not hard to draw parallels between hunting unicorns for their horns and rhino poaching, and the book also has interesting things to say about the tension between the protection afforded by conservation projects and the vulnerability to exploitation of animals that are not allowed to roam free in their natural habitat.
Lewis and Rhona are great characters, with plenty of depth to their contrasting personalities, and troubled family backgrounds that produce very different results - Lewis is withdrawn and sullen, while Rhona is determined to make the most of her trip away from home.
But the stars of the book are, of course, the unicorns themselves. As tall as a police Clydesdale, black, white, or silver-grey, without a speck of glitter in sight. Wild and magical, and very, very dangerous.
Highly recommended.