at the end of the season, as Praeger learns Lindsay has betrayed him by leaking information, meant to expose Elsinger's questionable ethical activity. Praeger offers his resignation, and Elsinger offers Peter Axon the case manager position. Season three Starting with the third season, Nigel Bennett and Peter MacNeill as Frank Elsinger and Ray Donahue respectively are added to the opening credits, after having guest roles throughout the first two seasons. Peter Axon and Curtis Rollins continue investigating the Arch and try to get Anton back. As Peter convinces Lindsay to come back to the team, Praegar also returns to the team. Anton eventually comes back from the Arch and is in the hospital in critical condition. It's revealed that Anton's wife, believed to be dead, comes back from the Arch as well. The return of Nicole Hendricks solves a 12-year-old case in which Anton's wife and daughter disappeared after a car crash. In the two-part third-season finale, "Forever and a Day", Michael Kelley returns and informs the team of The Chairman, a mysterious figure who is believed to be evil and immortal and control a series of interlocking companies, including Veritec, Tessler Industries and the O.S.I.R. They then begin a secret case in which they discover the identity of The Chairman and exorcise the demon. The end of the third season marks the final appearances of many original characters, including Curtis Rollins, Frank Elsinger, Ray Donahue, Lennox Q. Cooper, and Michael Kelly. Season four Starting with the fourth season, Nigel Bennett and Peter MacNeill are removed from the opening credits, while Soo Garay as Dr. Claire Davison is added to the opening credits, after having guest roles throughout the first three seasons. Joanne Vannicola joins the main cast as Mia Stone. With Elsinger apparently gone, Anton Hendricks has taken over the role of Director of Operations and very rarely takes part in the investigations over the course of the season. Hendricks enforces rotating case manager, leading Peter, Lindsay and Mia to take on the case manager position for different cases. In the fifth episode of the season, "883", Matt Praeger is infected with a virus which will lead to his death. The team soon discovers a secret project where a doctor is planning on colonizing a new world. Praeger learns the only way he could live is if he goes to the new world. After agreeing, he shares a tearful