Zelena, her grown daughter Robin and the Wish Realm’s Captain Hook stare down a sinister someone (or something) in this exclusive look at Once Upon a Time‘s first episode of 2018, airing Friday, March 2 and titled “Secret Garden.”

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“It’s pretty hashtag #LifeAndDeath, I’m not gonna lie. It’s hashtag #StakesAreSupesHigh,” Rebecca Mader, who returns to the ABC series tonight at 8/7c, tells TVLine of the scene above. “It’s definitely an intense moment — and a really heroic moment for Zelena, which I love. This is another moment where she puts herself on the line with a selfless act. It’s a lot of growth for my character, which I like.”

Once co-creator Eddy Kitsis meanwhile had this share about the scene, which features among other things a crystal ball in the foreground: “That room has no windows and no doors, and only one way out” — à la the Stretching Room from Disney’s Haunted Mansion attraction. “That’s a clue, for real!”

As for the school blazer sported by Robin (Riverdale‘s Tiera Skovbye), she is not attending Hogwarts (“Unless Disney bought Warner Bros…. which could have happened, we don’t know,” Kitsis says. “I havent looked at Deadline in the last 10 minutes”), but “she does appear to be practicing some witchery.”

Here, Mader shares more scoop on about her multi-episode encore as Zelena… and her new cursed persona, San Francisco spin instructor “Kelly”:

TVLINE | Tell us about Kelly….

REBECCA MADER | [Affecting a Valley Girl voice] Kelly is awesome. She totally loves working out and doing super-healthy things…. She’s so different from Zelena, it’s hilarious. When Adam [Horowitz] and Eddy first told me what they were thinking for my cursed person, I completely cracked up laughing, because it’s the antithesis of Zelena. Like, when has Zelena ever gone to the gym? Ever? [Her class] is basically supposed to be SoulCycle, which is essentially a cult. I’ve lost a lot of friends to spinning, it’s kind of sad! [Laughs] It’s like the friends you lose to CrossFit, where it’s all they talk about and they have their own lingo…. I actually went and took a SoulCycle class here in Vancouver just to sit in the back and study the teacher, and I was like, “This is one of the worst things I’ve ever done. I just want to go home and have a cup of tea,” but I got through it. It’s really hard!

TVLINE | What’s the dynamic between Kelly and Roni (Lana Parrilla) when they reconnect?

It ain’t great. It ain’t great. There’s an echo of [when Zelena and Regina first met in] the other realm, that contentious relationship and the anger…. There’s a history between them that is similar to Regina and Zelena’s.

TVLINE | And in this week’s flashbacks to the other realm, at the “Emerald Acres Farm,” why does Regina show up to find Zelena?

What can I say — she needs me. She needs her sister, which is great. Obviously the Evil Queen and Regina are superpowerful, but I think the sisters are stronger together. I have some powers that will help her “save the day”, and ultimately the two of us coming together is incredibly powerful.

TVLINE | Indeed, your first episode back really leans into the sisters’ bond and reminds us of how far they have come from Day 1.

I love their relationship; it’s the only one that is a sibling relationship as opposed to romantic. The fandom can ‘ship a romantic thing, but a lot of people ‘ship our friendship/sisterhood, and it’s cool to have this example to show women that they can have each others’ backs. And it’s not just our TV personas but also in real life. [Lana and I] are incredibly close and we share our relationship public with the fandom on social media and that’s really empowering. It all supports the message, “We’re stronger together.”

Want more scoop on Once, or for any other show? Email InsideLine@tvline.com and your question may be answered via Matt’s Inside Line.