When the second half of season 6 of "Pretty Little Liars" returns in January, viewers will see the grown-up versions of the Liars – Aria, Emily, Hanna and Spencer.

We got a glimpse of them towards the end of season 6 mid-season finale when the Liars came back to Rosewood to warn Alison about the new villain – someone they refused to name, but identified as "He."

A short promo for the upcoming instalment and photos from the set have given viewers an idea about what the Liars will be up to in the season 6B. At the same time, fans have come up with various theories and plot speculations, which include a possible affair between Aria and Ezra.

For instance, the Instagram account Pretty Little Logics predicts that Aria will be married to someone else in the second half. But that will not stop Aria from having an affair with Ezra, who will probably be running the new brew in town.

Another post on the Instagram account notes that the new villain coming after Alison in season 6B will be referred to as the Big Bad, and that he will be the new A. The Big Bad will be much more dangerous than Charlotte, who was revealed as A in the season 6 mid-season finale.

The new mystery will spill over to season 7, which could be when the series comes to an end.

As for what to expect in the second half of season 6B, executive producer Marlene King revealed to The Hollywood Reporter that when we return the girls will still be living in different cities.

Over the years, they have tried to keep in touch with each other through social networking sites. But over these five years they have accumulated a lot of secrets, which they aren't yet ready to share.

"The girls have spent five years apart — they've had five "A"-free years of life just to live a normal life — as normal as they can, having survived all of this. There's a very great scene in this first episode back where Aria (Lucy Hale) talks a little bit about the residual "A"-ness affecting her life, and it's great performance. She did an amazing job with the scene. So they come back together — they've been apart for five years — and they're very excited to see each other, but they still have secrets, too. They've had five years of being apart to need to cover up some of what they've been doing," King noted.

"Pretty Little Liars" will return to ABC Family in January.