We are just hours away from the CW's "Reign" premiere of episode 18, "No Exit" and we have some major spoilers for you as a new photo of a certain guest cast member has been revealed.

According to Access Hollywood, in Thursday night's episode we will see the arrival of Mary's half-brother in the French Court.

The new photo features Adelaide Kane's Mary Queen of Scots meeting with her half-brother James, who is there to warn her about troubles in Scotland.

James, played by guest star Joe Doyle, will beg Mary to return to her homeland. Apparently the Queen of Scot's mother, Mary de Guise, is in terrible danger with people threatening to turn against her. However, there are doubts on whether or not James can be trusted.

Mary will find herself torn on whether to be the Queen she was meant to be or stay in France by Francis side.

Speaking of the blonde royal, the heir will be worried about this James' presence and questions why he so desperately wants her back in Scotland.

Maybe there's a reason he should be worried. For those of you who can't wait to see what happens in tonight's episode check out the full Wikipedia summary of "Reign" episode 18.

Below is a MAJOR SPOILER! If you do not want to know what happens in "No Exit" stop reading below. The Wiki summary reads as follows:

"Mary's half-brother James Stewart, Earl of Moray (Joe Doyle) arrives to tell her that the Scots are chafing under Marie de Guise's rule and advises her to return to Scotland. Mary wants to go immediately but Francis is reluctant.

"Francis discovers James' footman was paid by the English to kill Mary during her voyage so that James can be king.

"When Mary still insists on going, Francis locks her in the tower. Catherine and Kenna work together, staging an intervention where a fake "Bishop" condemns Henry's sexual activities and scares Henry into humility and dismissing Penelope.

"When this succeeds, Catherine gives Penelope's estate and jewels to Kenna and Bash, who celebrate with a kiss. Lola and Julien are married, but Lola starts to suspect that Julien has financial difficulties.

"Nostradamus and Olivia have started a romantic relationship, but when Nostradamus has a vision of Olivia's death, he sends her away to Trinidad alone, knowing that Catherine will never let him go."

"Reign" airs Thursdays at 9 p.m. on the CW.