Castle - Episode 1.09 - Little Girl Lost - Plotline and Casting

STORY LINE
Castle helps the detectives search for the murderer of a long-underground radical bomber...

[WILL SORENSON]
35-38, an attractive and very confident FBI agent. He previously worked on a child abduction case with Det. Beckett (Stana Katic), and has been brought in to work on a new case with similar characteristics. He and Beckett had a past personal relationship, which will push him to go toe-to-toe with Castle (Nathan Fillion).sptv050769 GUEST STAR, 2 EPISODE ARC

Source: SpoilerTV