In Sunday's episode of Tracker season 3, episode 18, Colter Shaw uncovers new clues about his father's mysterious past tied to a secretive government research facility. The installment points toward a DARPA-funded operation that ended in an accident and introduces Dr. Serena Jukic as a key figure. Colter leaves a voicemail for his brother Russell, teasing Jensen Ackles' return in the May 24 finale.
Colter Shaw tracked down Buck Avery, played by Michael O'Neill, to learn more about his father, Ashton Shaw's, activities in the Alaskan wilderness before his death. Buck confirmed knowing Ashton and revealed that his family had leased land to government contractors for a secretive facility called the Chronostasis Institute. The site, allegedly funded by DARPA, conducted weather experiments and other unusual research before an accident led to its abrupt shutdown, with all traces erased as if it never existed, Buck told Colter.