On Nov. 22, Netflix’s animated series The Dragon Prince returned with its third season, challenging the cast of young heroes to stand up for what’s right, even if that means making tough choices.

The season starts off with the main cast separated. Young crown prince Ezran heads back to Katolis to assume his place on the throne, while his stepbrother Callum and Moonshadow elf assassin Rayla trek to the magical land of Xadia to return the baby dragon Zym to his proper place. The season marks some big moments for the plot, and for the characters’ interpersonal relationships. But while the writers sketched out an overarching story for a seven-season plan, the smaller moments came as a surprise.

[Ed. note: This piece contains major spoilers for season 3 of The Dragon Prince.]

In episodes 4 and 5, “The Midnight Desert” and “Heroes and Masterminds,” Callum and Rayla confess their feelings to each other and share a kiss. In another series, that surprise might have been saved for the aftermath of the climactic battle. Here, it comes early on in the nine-episode season, reshaping the episodes after it.

While the pairing seems natural — Rayla and Callum are the closest in age of all the main cast, and the bulk of this season features them alone together — their romantic pairing wasn’t originally in the cards for this season. Or for any point in the show, actually.

“That was not planned in season 1,” head writer Justin Richmond told Polygon in an interview ahead of the season’s release. “If you’d asked me, ‘Are they going to get together?’, I’d be like ‘Probably not.’”

But as the characters took shape with the whole writing team involved, they drove the story away from the original plan. For instance, Ezran was originally supposed to head into Xadia with Callum and Rayla at the end of season 2. But after reflecting on the character, the team realized he wouldn’t make that choice.

The Callum-Rayla romance sparked in a moment during the storyboarding phases of season 2, when the pair sat down for a heart-to-heart. A lingering glance on Rayla’s part prompted the writing team to consider the potential of the duo, and they continued developing it through the rest of season 2.

“There was a moment in the storyboards [later in the season] where she picks Callum up, and she’s definitely about to say a bunch of mushy stuff,” Richmond says. “Then she gets cut off because he wakes up.”

The Dragon Prince writing staff are aware of the possible relationships their fans are hoping for, say the creators, and “good ships and trash ships” are a source of constant chatter and scrutiny in the writers’ room. After a season 2 creative retreat, a gallon of corn oil inspired writer Neil Mukhopadhyay to put a name to those moments that leave a bit too much room for romantic possibilities. “Shipping oil” became the go-to slang for when scenes felt slathered with dialogue or character blocking that could send the wrong message.

When it came to Callum and Rayla, however, the team went with it. Though season 2 was the genesis of Callum and Rayla’s romantic feelings, it was season 3 that pushed the characters along, especially with the two of them off on their own in the magical land of Xadia.

“Going into season 3, there’s those speeches in the middle of [the first episode] where [Rayla] is defending Callum to Sol Regan,” describes Richmond. “I think that just added to the fire. And then we get to the Oasis and, you know, it’s really hard to be in an oasis at night with all kinds of romantic feelings!”

Though there’s no word yet on season 4 — and whether Callum and Rayla will remain a couple — there’s plenty of other Dragon Prince-related media on the way. Wonderstorm is actively staffing up to bring the Dragon Prince video game to life, while a full line of books from Scholastic are due in the first half of 2020.

“Aaron [Ehasz] wrote a core novel that sort of tells the full story of Book One [Moon]. It’s not a novelization, it’s a full-on core novel that has stuff you’ve never seen before. It reveals things about characters and all kinds of cool stuff like that,” Richmond says.

While plans may be sketched out for how the expanded Dragon Prince universe will take shape, considering how Callum and Rayla’s unplanned romance became a core part of the third season, other unexpected pairings or connections could fuel the future of the franchise.