The first episode in the two-part season finale of "The Blacklist: Redemption" is expected to unmask the mystery of Whitehall with some familiar faces.

The trailer for the episode called "Whitehall" shows that Tom Keen (Ryan Eggold) will turn to his wife for help to learn the truth about the mysterious Whitehall operation.

Tom's wife happens to be the FBI agent Elizabeth Keen (Megan Boone), who is known as the protagonist from the principal series "The Blacklist," together with Red (James Spader). But she will not be the only character from the original series who will cross over to the spin-off series. According to a report from ScreenerTV, Harold Cooper (Harry Lennix) will also appear in the episode.

There are no confirmed news about the possible appearance of Red in the spin-off, but fans are still hoping to see him interact with Tom and his long-lost mother Scottie Hargrave (Famke Janssen) before the final episode of the season.

Meanwhile, the synopsis reveals that the tension between Scottie and her husband Howard (Terry O'Quinn) will escalate. This will be the driving force that will lead Tom to seek the assistance of an unexpected ally. However, it does not provide any clues about the identity of Tom's surprise supporter.

The episode will also uncover more family secrets involving Tom and his family, after the former discovers that his father Howard could be in danger at the hands of his mother. Based on the trailer, it will still take a long while before Tom can fully trust her. But can Scottie fix her relationship with Tom soon?

The first episode in the two-part season 1 finale of "The Blacklist: Redemption" will air on NBC Thursday, April 6, at 10 p.m. EDT. It will be followed by the episode called "Whitehall: Conclusion," which will air one week after on April 13.