Mona might be gone for good, but "A" is still on the loose. This does not mean, however, that Rosewood has no room for more troublemakers. Series creator Marlene King shared a teaser for the return of "Pretty Little Liars" season 5 next year, saying that the Liars will get to know another character in January. 

"In the episode where Mona met her demise, she was talking to her friend Lesley on the phone that day and we finally get to meet Lesley. She comes to town," King stated. 

If Lesley is friends with Mona, could it mean that she will be on the Liars' side, or will she make their lives more miserable, if that could even be possible considering that there are Ali and "A" to think about. 

There is no news yet on who will portray Lesley in the show, and when will she arrive in Rosewood. 

But apart from Lesley, other characters will be introduced in "Pretty Little Liars" season 5B. There's Rebecca, a lawyer who will have a constant interaction with the Liars, to be portrayed by Lauren Tom. A good-looking British guy named Colin who is friends with Melissa will also drop by Rosewood, and he will be portrayed by Oliver Kieran Jones. Then Claire, a stylish pageant coordinator will also be introduced this season, and she will be portrayed by Anne-Marie Johnson. They will all appear in episode 21. 

Meanwhile, the official synopsis for the midseason premiere of "Pretty Little Liars" season 5B has been released, and it reads: 

Three months have passed, and Mona's friends and family are still mourning their loss and more adamant than ever that Alison had something to do with Mona's death. Ready to put "A's" game to an end and get justice for Mona, the PLLs ramp up their search for evidence that could prove Alison killed Mona. But with Alison claiming her innocence and having a seemingly airtight alibi, the Liars may have to resort to more shady tactics to put Ali away. 

Meanwhile, Emily and Paige reach a crossroad in their relationship, and Aria starts to worry about her future. 

Will the Liars finally give Mona the justice that she deserves? 

The "Pretty Little Liars" season 5B premiere episode titled "Through a Glass, Darkly" airs on Jan. 6 on ABC.