WATCH: Helen Mirren is Shockingly Scary in 'The Good Liar' Trailer

The Good Liar stars both Dame Helen Mirren and Sir Ian McKellen. The cat-and-mouse thriller starts off with McKellen's character Roy, who is a career criminal conning women out of their savings. Enter Mirren, as said mark, Betty.

At first glance, she appears to be falling in love with Roy (and the feelings may be reciprocated) and easily duped. But now that there is a second trailer, it appears she may have plans of her own.

At 0:40 in the below clip, we find Betty sitting in a dark room, all alone, with the lights off. And when the lamp pops on, she appears to be waiting on someone. Betty gives a little speech, saying, "You know, it's very peculiar. Doing things you'd never imagine. Secrets between you, God, the Devil and the dead... [Insert very dramatic pause]... You're becoming a very good liar."

WHO is she talking to? Maybe you can make it out from the new footage:

She might be talking to her son, played by Russell Tovey. And, who knows, maybe she's in on it with Roy? There's the chance she's looking in a mirror... but, that's unlikely, because we can see the outline of someone standing in the door, facing her.

It's all up in the air at this point, but this trailer worked on us, we very much want to know more.

The Good Liar hits theaters on December 20. There is time to go back and read Nicholas Searle‘s 2015 novel, which the film is based on.

Are you going to get a head start and read ahead!!??