Colter Shaw

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.