Fans will have to wait a bit more before they can watch "Criminal Minds" season 12 episode 20 as the airdate will be on April 26. The new episode will see Jane Lynch return as Diana Reid and the Behavioral Analyst Unit (BAU) investigates an outbreak of heart attack.

According to a report from CarterMatt, the new episode is moved to April 26 because of the "Survivor: Game Changers" show. The show will have a two-hour edition on April 19 to compensate for their late start to the season.

As for what will happen in episode 20, the synopsis revealed that the BAU will deal with some sort of heart attack outbreak as several federal government employees succumb to symptoms of heart attack. One of those who is affected is even a close friend of Stephen Walker (Damon Gupton).

The real excitement with episode 20 is the return of Lynch as Diana Reid, the mother of Spencer Reid (Matthew Gray Gubler). The synopsis revealed that Spencer will be anxious while awaiting his trial date.

The report said it will be interesting to see how Lynch will be incorporated into the story, considering that Spencer is separate from the group. Having Diana appear in the court is also not a good idea, considering her battle with Alzheimer's. So the writers would need to be creative to properly include her.

ComicBook reports that this development will be interesting because it was always Spencer who was doing the caring between the two. But now it's time for Diana to return the favor and care for her son's mental wellness during this trying period.

The "Criminal Minds" season 12 episode 20 s entitled "Unforgettable" and fans might want to make sure they catch the remaining episodes of season 12 will only have two more episodes after episode 20. It is believed that Derek Morgan will make a return during the season finale. Check out the promotional photos for "Criminal Minds" season 12 episode 20.