This young adult novel is about a young boy, and his grandmother who opens the "wrong" email.
Sam is your average ten-year-old resident of Britain. His Gran is staying with him while Mom and Dad go hiking up European mountains. The two have a strong connection, because they are both "cunning people." This means that Gran is teaching Sam what herbs, and incantations, to add to his baking to, for instance, hypnotize people, or force them to tell the truth. This means that they have dealt with various beasts and goblins that are invisible to the rest of us.
Gran is an internet beginner, so she believes an email saying that she has won a chance to meet Aaron Kid, her favorite TV chef, in Edinburgh, Scotland. Sam is skeptical, to say the least, but off they go. They stay with Mungo and Lottie, who are fellow cunning people. Mungo's eyes don't point in the same direction at the same time, and Lottie is physically frail, due to some ailment that is beyond the reach of human and cunning medicine.
Sam's skepticism is justified, and Gran is kidnapped. The whole thing has been orchestrated by a woman named Tabetha. Gran, Lottie and Tabetha were classmates, and good friends, when they were children, but something happened, and Tabetha is now looking for some serious revenge. Sam travels in the tunnels under Edinburgh, looking for help, a mission which, at best, is very foolhardy. Does Sam find, and rescue Gran, stopping Tabetha once and for all? Meantime, the stress of worrying about Gran, and searching for her in the damp Edinburgh climate, has pushed Lottie's condition from frail to critical. Can anything be done for her?
This one is surprisingly good. It is intended for 9-12 year olds, but older children, and maybe some adults, will enjoy it, too.