In "Reign" Season 2, Episode 20, "Fugitive," Mary learned from Catherine that Condé proxy-married Queen Elizabeth. She confronted him and told him that he had committed treason.

"My treason was in loving you," he said.

Bash told Francis that Condé was plotting a Protestant rebellion against the throne. Francis' anger toward Condé grew when he learned Mary had not ended her relationship with him.

"The punishment for treason is death. I cannot allow him to live," Francis told Mary.

Bash and his soldiers failed to rescue the kidnapped boys, but not before Bash caught a glimpse of their bodies marked with Louis Condé's Bourbon crest. The false evidence surely was planted by Narcisse's men.

When Condé learned that he had been set up, he told Mary that he was leaving and begged her to join him. It was a key moment when we learned where Mary's allegiance truly lies; the Queen of France told him that she could not leave Francis's side or her station.

Greer and Kenna had a celebration at Greer's house after dark. When Captain Renaud arrived to celebrate the victory of saving the kidnapped children, Kenna crossed the line with him.

Meanwhile, Lola ran into Narcisse on her way back to court. The unrequited attraction between them quickly surfaced.

In Episode 21, "The Siege," Mary's loyalties are tested when she makes a heart-wrenching discovery.

Troops are about to storm the castle, forcing Mary and Francis to put aside their differences. Together, they determine the extent of Condé's betrayal.

Meanwhile, Catherine decides to teach Narcisse a lesson to prove he can never cross her again.

Bash, who has apparently been living in the woods with a psychic nun named Delphine (guest star Alexandra Ordolis), decides to bring her to the castle.

Watch "Reign" Episode 21 "The Siege," which airs on Thursday, May 7, at 9 p.m. ET on The CW.