Dr. Reid (Matthew Gray Gubler) is slowly remembering the events in Mexico that led him to be accused of murder, wherein his mother could have a bigger involvement than what was lead on. Meanwhile, Shemar Moore is excited to make his appearance on the series.

On the next episode of "Criminal Minds" season 12, titled "Unforgettable," federal employees are being targeted by the unsub.

"When several federal government employees, including a close friend of Walker's (Damon Gupton), succumb to symptoms of a heart attack, the BAU investigates. Also, Reid anxiously awaits his trial date," the episode listing on The Futon Critic reads.

Meanwhile, Reid is slowly remembering the events that led him to be accused of murder with the help of Dr. Tara (Aisha Tyler). With some of his memories coming back, Reid is both eager and anxious to face his trial because he can finally prove that he's innocent of the charges against him.

Previously on the show, Reid remembered that a woman was with him in the room who expected him to follow her. Although there are no hints who the mystery woman is, one possibility is that it could be Reid's mother, Diana (Jane Lynch), who is confirmed to be making an appearance in the upcoming episode 20.

However, it is possible that Reid will get a visit from his mother or that there will be flashbacks of their times together.

Meanwhile, Moore is confirmed to return in the season 12 finale of "Criminal Minds," and the actor is very excited to come back to the show.

While guesting on Access Hollywood, Moore teased what the viewers can expect from his appearance.

"It's going to be quick and simple, but it's in the finale episode. I'm going to be back with the team. I'm going to be flirting with my original baby girl Penelope Garcia," the actor shared.

"I can't tell you what I'm doing but I'm gonna come in and I'm gonna stick a move," he went on to say.

"Criminal Minds" season 12 airs every Wednesday night at 9 p.m. EDT on CBS.