Pepper Karalis, technowitch, has interacted with the trolls in Boston's T before. They've warned her about problems in the bedrock of magic — holes, cracks, quakes. Now they want her to fix it. She can't see the magic as they can, so she has to partner with a troll to do the work. Too late, she realizes not everyone wants her to succeed. Can she evade the traps set for her, repair the material of magic itself, and still manage to make her court date for the custody suit her ex has brought against her? Troll Tunnels is the third book in the Boston Technowitch series.