Bates Motel” returns for its fourth season on March 7 on A&E, and showrunner Kerry Ehrin promises even more high-stakes drama, as Norma (Vera Farmiga) finally comes to terms with Norman’s (Freddie Highmore) increasing instability.

“We think it’s the best one yet,” Ehrin tells Variety of Season 4. “Everything is firing on all cylinders. The writing is great. The performances are amazing. Vera and Freddie have topped themselves this year.”

Where does this season pick up?

This season picks up directly after the end of last season. It’s the same night. Norman is deep in a blackout. He doesn’t know who he is or what he’s doing. He’s lost basically in the aftermath of the Bradley killing. And Norma has an awareness that Norman was in a terrible blackout. She believed Bradley was with him. She doesn’t know if that’s true or not. She and Dylan have ben searching for him all night. And she doesn’t know if she’ll ever him see him again. You can imagine how scary that would be for a mom.

What’s the theme of this season?

At its heart, this show is always going to be about the bond between Norman and Norma — that sort of strange emotional marriage they have and how the world is going to try impede on that. They’re always going to try to push it out and stay connected. They might not always be able to. But at its heart that really is the north star of the storytelling of the show. And on a thematic level, the show is about hope, weirdly, and trying to discern reality from delusion. Those are two huge themes this season.

Norma has finally realized Norman needs help. What lengths will she go to?

She has hidden for a long time from herself facing that she in and of herself is not enough to fix him. All the love in the world is not going to fix him. She’s been terrified to the point of “he’s lost, he’s in a blackout,” she can’t find him. She knows that it’s time to look outside of herself. That’s really challenging for her because she’s really dependent on him. She’s also terrified that he’s going to get taken away from her. She’s afraid of the truth that there’s really something really, really wrong with him.

Should she herself be scared of him?

She’s definitely starting to put up a little bit of an emotional boundary between them. Because on some deep level, she is afraid of him. Or afraid of what she thinks he might be capable of. She is always going to love him because he’s her kid and that’s built into you, you can’t help it. But everything that’s happened, that’s suspect, it can’t all be explained away. Enough has happened that leaves her in doubt as things begin to unfold in the first two episodes — that becomes a real crisis question for her.

Is Norman aware of his own unravelling?

Yes, to the extent that he is aware that he loses track of time. That he wakes up in places that he doesn’t know where is. That he thinks he’s had conversations. He’s aware that his understanding of reality is not always accurate.

What’s his perspective of his relationship with Norma?

He’s starting to question her, definitely, because he gets visited by Mother during some of his darkest moments. Even though he can’t consciously remember that, there’s a part of his body that will remember that. And that makes him question her and question her motivations. The more she tries to control him, it makes him question if she has an ulterior motive for doing it. It’s very cat and mouse.

Who’s in control: Norman or Norma?

That’s a huge part of the first two episodes. It’s a very heated battle in the first two episodes. It comes to a really huge climax at the end of the second episode. Because they’re both very strong, controlling smart people. Once they start trying to outmaneuver the other one, it becomes really interesting.

How much more closely is he becoming the Norman Bates we know from the movie?

The Norman we know from the movie is this polite, nice, welcoming guy who lives with his mother who sometimes kills people. In a lot of respects, he is that guy now. We have arrived at that guy.

Will he kill again this season?

He is Norman Bates. (Laughs.)

Those Norman/Norma scenes are so fantastic. What’s the experience of filming them? 

Those two together — they’re a double scoop of ice cream. It’s a fun experience to be on set when you have a Norman/Norma scene. Their chemistry is so good. It becomes so real. I always start getting ideas for other stories when I’m on set. “Norma in this situation would do that.” It’s such an amazing reality when those two get together.

Let’s talk about Norma and Romero. Why is he willing to kill for her?

Because he cares about her, whether or not he wants to say that out loud. I think Romero’s lived a very solitary life. He’s super guarded. Usually when people are that guarded it’s because they’re vulnerable, because they’ve been hurt. The fact that she’s gotten under his tough skin is unsettling to him. He’s not used to having a vulnerability in the world. I think part of him would like to walk away from it immediately. But she’s a pretty compelling woman. He’s drawn to her even though he doesn’t want to be. He’s a good guy and he gleans that she’s in a dangerous situation and he wants to help her. And that she’s desperate.

Sounds like the making of a toxic relationship.

You think? (Laughs.) That is the question. Can Norma have a good relationship? Is she ever going to have that kind of growth to step out of her own demons and dysfunction and her own past and have some sort of healthy relationship with a man that isn’t her son?

Will it come out that he killed Bob Paris?

Killing Bob Paris is a huge part of his character. When the show starts that was definitely off his normal moral compass. Yes, Bob Paris was a bad guy but he was set to go to prison. It would have been a perfectly acceptable handling of the case but Romero wanted to protect Norma and he did something that was not particularly the right way to handle it. The fact that he grew up with him and he did that is haunting to him.

What about Emma? Safe to assume she’ll survive the lung transplant?

We hope so. The thing about a lung transplant is that isn’t like you put the lungs in and hey, you’re fixed. It’s a foreign organ in you and you have to constantly monitor it. That’s something she’s going to have to live with her whole life.

What does that mean for Emma and Dylan’s relationship?

It means that it’s not to be taken for granted. That this island of peace and meaning that they’ve found together in the midst of all this chaos is sort of sacred. Not necessarily it’s a given that’s forever. We hope it will be. They are a wonderful island in the crazy chaos of “Bates Motel.” They’re both good people who have found somebody who sees them and appreciates them. They can be happy in that. It’s just a question of “can they evade the chaos?”

Will you be introducing any new characters this season?

There’s someone from Romero’s personal life, which has always been off screen and always been a joke. Who is Romero sleeping with? We never see him with anyone. We open that up a little bit and we find out more about someone in his life who comes into play. There’s also a wonderful doctor at the mental institution who becomes a huge influence on Norman.

Freddie Highmore joined you in the writers’ room this season. What did he bring to it?

He was great. We were all crazy about him. We didn’t want him to leave. He’s just an incredibly smart, articulate, thoughtful person. This is someone who has studied characters and story structure since he was 7 years old. He completely understands how you break down a scene. What a character motivation is in a scene. He writes from character. It was great to have him in the room because we got so much from Norman’s perspective in this episode. We basically had Norman to write it with. That’s about as clear a perspective as you’re going to get. Norman can write Norman.

“Bates Motel” Season 4 premieres Monday, March 7 at 9 p.m. on A&E.