I read the book in two days, which tells you how good I think it is. I was lucky enough to see the authors speak at the Hay Festival last weekend - they summed up their book up as "Twins use Gifts to fight THE EVIL!"
That's exactly right. I wont' give any spoilers away here - simply to say that this is wonderful story of a pair of twins, on the cusp becoming teenagers, who find new abilities "Gifts", awakening in themselves, which they must learn to master in order to quell the evil force that threatens their town. And because the twins are just learning how to use their powers, they don't always get the results they want. They are helped along the way by their intriguing Grandma X (who knows a lot more than she's letting on) and also by two cats - Kleo and Ari (some enjoyable shades of Mogget from the Abhorsen trilogy here).
I loved the twins powers, which all come from nature and the environment around them and young readers will particularly love some of their gruesome battles with ants, cockroaches and rats!
The second book in the series has been finished so should be published soon and a third book is in the planning stage. That said, this story stands on its own and at the end I found myself looking forward to reading new stories about the twins.