Santa has come early for “Pretty Little Liars” fans. While the hit ABC Family show might be on hiatus, the Liars will return for one night on Tuesday, Dec. 9 for a special Christmas-themed episode. Since the series has been off the air for a couple of months, some viewers might be a little fuzzy on where the teen drama left off. Fortunately we’ve got the scoop on what went down in the summer finale, and what fans can look forward to during the holiday special, “How The ‘A’ Stole Christmas.”

By the time the Aug. 26 finale rolled around, the season had done a 180 from where it had begun. Alison (Sasha Pieterse) had gone rogue and became a major threat for Aria (Lucy Hale), Spencer (Troian Bellisario), Emily (Shay Mitchell) and Hanna (Ashley Benson). With their futures on the line, the girls had one last resort for help … Mona (Janel Parrish).  Mona had been a foe throughout a majority of the series, however the Liars knew one thing for sure – she wanted to take Alison down just as bad as they did.

With the former “A” on their side, the girls were able to hack into the police database system and find out that Alison had successfully convinced Detective Holbrook (Sean Faris) that she wasn’t involved in the murder of Bethany Young, the real girl that ended up in Alison’s “grave.” The only problem was that the police had a new suspect in Bethany’s murder – Spencer.

The Liars not only had to figure out what Alison was up to, but now find evidence to clear Spencer of any connection to the dead girl. Mona and Spencer broke into Radley and were able to steal Bethany’s files. But unfortunately the mission led Spencer to miss Toby’s graduation from the police academy. Her boyfriend called her up to question her about her whereabouts, and ended up getting into a bad accident while on the phone. Spencer was destroyed, but Toby made it out of the accident a little beat up with a broken leg.

Toby was lucky, but the girls got more bad news. Paige (Lindsay Shaw) had followed Alison and two of her minions, Mindy and Cindy, and discovered that Alison had managed to build an army of supporters and followers. On top of that, Detective Holbrook arrested Spencer for the murder of Bethany Young.

With their world falling apart, Mona managed to find one juicy piece of information in Bethany Young’s files that could change everything for Spencer and the other Liars. “Pretty Little Liars” fans previously discovered that Alison’s mom, Jessica DiLaurentis (Andrea Parker), had been having an affair with Bethany Young’s father. However there was a new development. It turns out that Alison had known about the affair and tricked Bethany to traveling to Rosewood. Alison was jealous of Bethany … and wanted her dead.

Mona warned Aria about her discovery. Aria called the others and they rushed to Mona’s house. But unfortunately it was too late. A blonde girl wearing a black hoodie and leather gloves had been watching Mona. She broke into Mona’s home and murdered her before she could show the girls what she found in Bethany’s files.

The Liars arrived at Mona’s house to find the place destroyed and blood smeared everywhere – but Mona was not there. The police confirmed that while no body was found, they were considering the investigation a homicide. In the final moments of the “Pretty Little Liar” summer finale, “A” stole the baby Jesus out of the Nativity scene on Emily’s front yard and replaced it with a Mona doll. She put the baby Jesus in the trunk of the car … which also held Mona’s dead body.

The "Pretty Little Liars" Christmas episode will pick up following the death of Mona and the arrest of Spencer. Rosewood will be decked out for the holidays, but needless to say the girls won't be in the mood to celebrate. That will all change though when an “opportunity presents itself” for the Liars to help Spencer clear her name. With evidence to help their friend on the line, the Liars will “devise a plan to get justice for Mona and finally bring Alison down.”

As the girls plot to get Spencer off Santa's naughty list, Alison will experience her own version of “A Christmas Carol.” The teen, who has wreaked havoc since the start of the series, will get a “glimpse at the past, present and future by a ghostly presence.” Fingers crossed Mona gets to torture Alison from beyond the grave!

The "Pretty Little Liars" Season 5 Christmas special will air on ABC Family on Tuesday, Dec. 9, at 8 p.m. EST.