Pretty Little Liars
Alison (Sasha Pieterse) will be released into the care of Mary Drake (Andrea Parker) in episode 5 of “Pretty Little Liars.” Freeform

Who is the mysterious Dr. Elliott Rollins?

Alison’s (Sasha Pieterse) husband may have been killed off last week on “Pretty Little Liars,” but his story is only just beginning. Episode 5 of the Freeform series will explore who the twisted doctor really is — a man named Archer Dunhill.

“Nothing he told me was true,” a visibly upset Alison says in the promo video for episode 5. “What his name was … where he was from.”

The synopsis for the upcoming Season 7 installment, titled “Along Comes Mary,” reveals that the Liars will succeed in getting Alison released from the psychiatric hospital — but there is a catch. Alison can only be sent home “into the care of a relative.” And with Jason (Drew Van Acker) out of town, the only relative in Rosewood to watch over her is her late mom’s estranged twin sister, Mary Drake (Andrea Parker).

Mary Drake is not the only person that Alison has to worry about in episode 5. Jenna Marshall (Tammin Sursok) made her grand return to Rosewood in episode 4, claiming to be in town for Toby’s (Keegan Allen) engagement to Yvonne (Kara Royster). However, it didn’t appear as if Toby actually invited his stepsister. An awkward run-in at the police station revealed that the two tried to make amends three years ago and that it “didn’t go well.”

So, is she actually in town for another reason? According to the episode description, she’ll “befriend another one of the Liars’ enemies.” Pair that with her call on Elliott’s (Huw Collins) burner phone last week and it looks like we’ve got a new suspect on our hands! But how exactly did she get to know Elliott — or should we say, Archer? Aria (Lucy Hale) and Emily (Shay Mitchell) will stumble across a secret apartment that they hope holds answers about their tormentor.

“Pretty Little Liars” fans can also look forward to a new mystery as Caleb (Tyler Blackburn) goes missing. Spencer will have to put aside her differences with Hanna (Ashley Benson) in order to find him. But is Caleb really missing? The promo video teases that the episode will feature an “unexpected proposal.”

Catch Season 7, episode 5 of “Pretty Little Liars” when it airs on Freeform Tuesday, July 19 at 8 p.m. EDT.