WhenPretty Little Liars returns in January, the girls will find themselves tormented by a new foe who is even more dangerous than A.

Five years following the A reveal, the girls get roped into the new big bad's drama after Allison (Sasha Pieterse) asks them to return to Rosewood to help with Charlotte. But when the girls begin to receive messages again, it quickly becomes clear that this isn't the same old game.

"They know it's not from Charlotte. And this time it feels very different," Troian Bellisario says.

Rather than threatening to expose secrets or embedding messages in your teeth, this new foe is out for blood. This forces the girls to up their game in how they retaliate against their new tormentor. "Because it's life or death so quickly, you guys fight back right away," explains showrunner I. Marlene King. "I think that's a big difference between moving forward and the past."

See what else the cast revealed about the new big bad and time-jump in the sneak peek o fTuesday's Pretty Little Liars special below.