Watson is dead. Holmes is alone. And Jack is desperate.

Sixteen-year-old Jack Moreno is managing to hold his life together. Barely. After a terrible car accident leaves his father unable to work, Jack makes ends meet by dropping out of school and covering his dad's custodial shifts at a school for troubled teens, high in the Wasatch Mountains. Everything is going all right until the night Jack finds Sarah Watson—yes, descendant of that Watson—dead.

When the icy but intriguing Holloway Holmes—yes, descendant of that Holmes—learns of Watson's death, he is determined to discover the killer on his own. But Jack and his father are the prime suspects in the official investigation, and Jack refuses to sit by and wait.

In an uneasy alliance with Holmes, Jack must hurry to learn what really happened to Sarah Watson, which means facing down a Moriarty, unearthing secrets and blackmail, and trying to solve the other murder at the Walker School, one that happened more than twenty years before. Working together is the only way Jack and Holmes might find the killer before he catches up with them, but both boys are keeping secrets of their own—secrets that threaten the fragile trust they've managed to build between them.