Kidnapped Part 2 (Warning: possible spoilers)

Five years later, Caleb is a graduate student in forensic anthropology, training as an assistant to Professor Ben Sheridan. [Whom you met in Bones.] He's still convinced that Mason is innocent and that Jenny is alive. He finds an unexpected ally in a friend of Ben's — reporter Irene Kelly.

Irene has been writing stories about the abduction of children by their non-custodial parents. She's been getting calls all morning from readers, including people like Jane Serre. Two years ago her former spouse, Gerald Serre, picked up their young son, Luke, from day care for a scheduled weekend visit — and never brought him back.

Irene is later sent to a scene where Ben and Caleb are recovering the remains of a murder victim — and is shocked to learn that the victim is Gerald Serre. But if Gerald Serre is dead, what has become of Luke? Irene is determined to find out.