'Pretty Little Liars' Season 4B premiere: Whose side is Mona really on?

Check out these sneak peek clips of "Pretty Little Liars" Season 4B premiere, "Who's in the Box?"

Above, the girls wonder if Alison ( Sasha Pieterse) reached out to her brother Jason. What does he know about Ali's disappearance and/or her still being alive? Spencer ( Troian Bellisario) thinks it's something worth pursuing and we all know that if Spencer thinks you should do something, you should probably do it.

Below, look who's back in Rosewood -- Spoby, together again. Toby ( Keegan Allen) brings news of his mother's "suicide" at Radley, but you'll have to wait until the premiere to find out what it is.

And finally, Mona ( Janel Parrish), who is now toodling around town in Jenna's powder blue Mustang, tries to reach out to Hanna. But Hanna ( Ashley Benson) isn't having it. She's still not sure whose side Mona is on -- and neither are we, which is honestly just the way we like Mona.

"Pretty Little Liars" returns Tuesday, Jan. 7 at 8 p.m. ET/PT on ABC Family.

Photo/Video credit: ABC Family