Ep 21. There's Something About Mary

In Supernatural season 12 episode 21, titled "There's Something About Mary," the Winchesters continue their fight against the British Men of Letters and the looming threat of the American hunters turning against them. Meanwhile, a familiar face resurfaces to wreak havoc on their plans.

The episode opens with Sam and Dean brainstorming ways to take down the BMOL and their leader, Lady Antonia Bevell. As they discuss their options, they are interrupted by a call from their old friend and fellow hunter, Jody Mills. Jody informs them that she has found a lead on a powerful artifact that could help turn the tide in their favor, but it's in the possession of a former BMOL agent, a woman named Mary Winchester.

The Winchesters are shocked and skeptical at the idea that their long-dead mother could be alive and working with the BMOL, but they agree to investigate the lead. They travel to a small town in Missouri, where Mary is reportedly working as a nurse under an assumed name. They soon discover that Mary is indeed alive and well, and she has no memory of her life before waking up in the BMOL's custody.

As the Winchesters attempt to convince Mary to join their fight against the BMOL, they are ambushed by a group of hunters who have aligned themselves with Lady Bevell. The hunters reveal that Mary has been brainwashed by the BMOL into serving their cause, and they intend to take her back into their custody.

A tense standoff ensues, with the Winchesters and the rogue hunters battling for control of Mary. In the chaos, Sam is captured by the hunters, leaving Dean to fend for himself. With his brother's life on the line, Dean is forced to make a risky deal with Lady Bevell, putting both his and Mary's future in question.

As the episode comes to a close, the Winchesters and Mary are left to pick up the pieces and plot their next move. While they have gained a powerful ally in Mary, they have also made new enemies in the form of the rogue hunters and the BMOL. The future is uncertain, but one thing is for sure: the Winchesters will never give up the fight.