The girls are about to learn how bad Elliott (Huw Collins) really is in the upcoming episode of "Pretty Little Liars."

In the episode titled "Bedlam," CarterMatt reports that the Liars cannot help but be suspicious of Alison's (Sasha Pieterse) new husband. As her condition worsens, her friends begin to wonder if the treatment that she has been getting is helping her get well. As far as they are concerned, Alison is getting the best treatment in Radley for her hallucinations. Elliot has been nothing but a loving and supportive husband based on how he is always there for her. They cannot understand why Alison is scared to be alone with him.

Elliot wants Alison to suffer for what happened to Charlotte (Vanessa Ray). He also believes she is the one who killed her cousin. To get his revenge, Elliot conspired with Mary (Andrea Parker) to make Alison believe she was going crazy. This time, though, even Mary is telling him he is going too far. In the promo, she is shown telling her daughter's ex-fiancé that he should stop tormenting Alison. The Liars hear their conversation and they begin suspecting the truth.

Emily (Shay Mitchell), in particular, thinks something is off with Elliot. Alison is hysterical when her friend attempts to leave her alone with her husband. Later on, Emily starts questioning herself if she did the right thing by entrusting Alison's care to Elliot. As shown last episode, he is gearing up for the ultimate revenge on the blonde. He is convinced she killed Charlotte, just like the Liars. But unlike them, he does not need proof. Alison is a goner for him and the sooner she dies, the better. Will the girls discover Elliot's true identity before it is too late?

"Pretty Little Liars" season 7 airs Tuesdays at 8 p.m. EST on Freeform.