Abby Buckman, the three-year-old daughter of ADA Angela Buckman and her NYU lecturer husband Matthew, vanishes on a trip to the park with her nanny. The team suspects that Angela's work may be the cause of her little girl's disappearance, especially after she tells them she was threatened on the street by a man only days earlier. However, when they discover that Matthew was unfaithful to Angela before Abby's birth, they speculate that the student he had an affair with, who has recently been back in contact with him, could also be to blame. Despite many sightings and pieces of evidence that come into the office, the team hit a wall with every inquiry. That is until Jack and Sam look again at the bare facts of the case and propose that Abby may not have been the target of the kidnapper at all.