Who killed Sarah Harvey? That’s the question heading into episode 7 of “Pretty Little Liars” Season 7.

The latest installment of the Freeform series picks up with the entire gang celebrating Aria’s (Lucy Hale) engagement at The Radley. Although all of them have been bickering lately, Spencer (Troian Bellisario) gets everyone a necklace with their name on it. They’re a “crazy, dysfunctional family,” she admits — but they work better together.

They also immediately panic together. Police enter The Radley and they think that they’re there to arrest them for the murder of Elliott/ Archer (Huw Collins). But they’re actually there to investigate a murder — Sarah Harvey (Dre Davis). The girls are shocked to learn that Sarah was murdered, and suspect Jenna (Tammin Sursok) after Emily’s previous awkward run-in with them. However, Jenna’s just as distraught as them. She has tears in her eyes as she talks to the police.

What’s Jenna’s deal? Later that day, Spencer spots her old enemy talking to Toby (Keegan Allen). Spencer approaches Toby when she leaves, asking why she’s truly in town. She knows that Jenna didn’t return for his engagement and he finally reveals the truth. She came back to Rosewood to seek forgiveness. A flashback reveals that Toby and Jenna reunited for a family vacation. Things were going well until Jenna tried to kiss Toby.

That’s not the only family drama going down in Rosewood. Jason (Drew Van Acker) finally returns to town and is happy to reunite with Alison (Sasha Pieterse) — and happy to kick Mary (Andrea Parker) to the curb. He got a court order appointing her as Alison’s guardian and wants Mary off his property. Mary doesn’t fight him on it, but Alison does.

Jason argues with his sister that their estranged aunt was the reason why she was institutionalized. Alison doesn’t exactly see it that way though. She explains that Mary is the reason she’s out of the mental hospital. Yes, she did help Elliott steal from her. But when she realized that Elliott was taking things too far she did the right thing.

Jason’s still uncertain and interrupts Aria while she’s in the middle of planning on eloping with Ezra (Ian Harding). It turns out that something happened between her and Jason in the couple year time jump — something that no one knows about. Jason agrees to keep quiet about this secret, but he needs Aria’s help. Alison’s bank account wasn’t just cleared out. Money was stolen from the Carissimi group, and Jason uses that money to help kids in Ethopia.

Of course that’s not the only sneaky meet-up happening in town. Hanna (Ashley Benson) steals her mom’s hotel security card and breaks into Jenna’s room to snoop around. The room is clean except for a lockbox hidden under the bed. She’s trying to break into it when Caleb (Tyler Blackburn) enters the room. Hanna’s mom hired him as security at the hotel and he watched Hanna break into the room.

Caleb sneaks into the room to see if Hanna needs any help. Just like his ex, he believes that someone murdered Sarah, and he’s willing to steal Jenna’s lockbox key to investigate. He pretends to be a masseur and that The Radley is giving Jenna a free spa day to help her deal with Sarah’s death. Since he doesn’t actually speak, Jenna gladly accepts the offer, and he uses the moment to steal the key from her bag.

Hanna and Spencer take the key and go back into the room. They open the lockbox, but the laptop they were looking for isn’t there. Instead they find encrypted files about Mary Drake. They take photos of the files, but get cut short when someone else enters the room — Noel Kahn (Brant Daugherty). Hanna and Spencer manage to hide under the bed before Noel can see them, and they’re able to watch as he puts the old Radley file on Mary Drake into Jenna’s lockbox.

Earlier in the episode, Yvonne was attacked during a break-in at Toby’s airstream. Only one thing was missing — his file on Mary Drake.

While all this is happening, Aria is attending an awkward family dinner with Alison, Jason and Mary. Jason invited her, which makes Alison suspicious. She also eyes her old friend when she spots her grabbing Jason’s arm when he becomes irritated with his estranged aunt. But the dinner does becoming very telling when Mary reveals that she saw Jason once. “Pretty Little Liars” flashes back to the time that Jason showed up to his Aunt Carol’s house after the elevator accident. He was trying to spend the night and found his mom there. She refused to let him inside the house and now understands why — Mary Drake was inside. She came to ask Jessica (Andrea Parker) about her son and how he died. Jessica wouldn’t give her sister any answers, even though she secretly knew that Charles was alive and living as CeCe Drake (Vanessa Ray). Mary reveals that Jessica hid in the cellar of the house until she left. That immediately catches Alison and Aria’s attention.

Pretty Little Liars Jason (Drew Van Acker) return to town for Alison (Sasha Pieterse) in episode 7 of “Pretty Little Liars.” However, he’s not happy to see Mary (Andrea Parker). Photo: Freeform

Aria wants to go that night to investigate the cellar, but can’t because Emily (Shay Mitchell) is out celebrating her mom’s birthday. Spencer’s also busy meeting with Toby, who tells his ex that he’s leaving town with Yvonne (Kara Royster). It’s an emotional goodbye, especially since Toby finally confesses that he was building the house in Rosewood for Spencer. However, he also reveals that he didn’t realize how much he cared about Yvonne until he found out she was in the hospital. Spencer is in tears as Toby reveals that they’re going to move to a small town in Maine to start their family.

In other heartbreaking ex news, Hanna finally comes clean to Caleb about breaking things off with Jordan (David Coussins). But Caleb doesn’t try to make a move on Hanna. Instead he asks if she’s OK.

The juiciest ex tidbit goes to Ezra. He’s helping Aria pack to elope when the FBI knocks on the door. They reveal that they have reason to believe that his ex girlfriend, Nicole (Rebecca Breeds), is alive.

The episode ends with Alison, Emily, Hanna and Spencer finding the old storm cellar that Mary was talking about. They get inside and discover that Jessica was using it as her lair. Even though she buried her daughter, she knew that Alison had managed to get out of the grave. She was investigating everyone in town and had files on all of the girls. However, a file on Aria is missing. She also had full files on her sister. Documents inside the files reveal that she authorized electro-shock therapy on her twin. The papers also reveal that Mary had a second child. It’s not revealed if Mary had a boy or girl. The only thing that the papers say is that there were no complications due to the prior birth. Whoever Mary’s second child is, they would be the same age as the Liars … and it would make sense if they want revenge.

Episode 7 of “Pretty Little Liars” ends with the alarm in Spencer’s car going off right outside the lair. The keys are gone and the only way to stop the alarm is for them to close the doors. Once inside, a countdown begins. They think that the car is going to blow them up, but that doesn’t happen when it ends. Instead a message pops up.

“If you find out who I am before I find out who killed Charlotte, you die.”

Jessica’s lair blows up before the Liars can fully process the message. But their stalker isn’t done there. Hanna watches as the mysterious person writes “I see you” on the back window of the car.

When their stalker returns to his/ her lair, “Pretty Little Liars” fans watch as they throw Aria’s file on a desk … and burn Noel’s file.