Dark Angel — John Sandford

The second book featuring Letty Davenport, the tough-as-nails adopted daughter of Lucas Davenport, this time taking on an undercover case that brings her across the country--and into the most dangerous group she has ever faced.

When a group of hackers threatens to take over the power grid of Minneapolis -- putting thousands of lives at risk -- the Department of Homeland Security and the NSA team up to prevent the attack. They need to find out who these dangerous hackers are…and they need to do it quickly. Letty Davenport, the twentysomething daughter of Lucas Davenport, is brought on board to go undercover and infiltrate the group. Posing as a rogue programmer for hire, she and her reluctant partner from the NSA, Rod Baxter, head to Los Angeles to find the illusive group before it is too late.