Spoiler warning: this piece discusses the season finale of The Shards.

The Shards ended its first season the way any good whodunnit should: by putting everyone in one room and letting the cops eye each of them like they did it. Ryan Murphy's FX adaptation of Bret Easton Ellis's 1981-set thriller closed out with Bret, Robert, Debbie and her mother, Steven, Thom, Ryan and Susan all named suspects in the finale, titled "Stairway to Heaven." Terry, Debbie's father, is dead, thrown off a balcony. The Trawler is still out there. Or maybe not. Maybe The Trawler was in that room the whole time.

Kaia Gerber, who plays high schooler Susan, told The Hollywood Reporter she finds it strange to think of her own character as a real contender for the killer, and stranger still that the show is willing to entertain it. "We know it's one of us," she said of the ending.

Here's the thing about the source novel: Ellis never actually named the Trawler. The book stays inside Bret's head and leaves the mystery hanging. Gerber, though, is confident Murphy's version won't do that. Murphy has previously said he and Ellis mapped out three or four seasons for the show, and this finale only gets the story to roughly a third of the novel's ground. Which means there's a lot of runway left before anyone finds out who's guilty of what.

Gerber isn't shy about how tough Susan is to root for. "It's hard for me to empathize with Susan in certain moments — the relentless winning is infuriating. I like that everyone is very complicated and layered in their own ways," she said. She also pointed out something the book couldn't offer: Ellis wrote The Shards entirely from Bret's point of view, so every other character, Susan included, exists mostly in relation to him. The show doesn't have to work that way. "As one of the characters who isn't Bret, I appreciate that we're getting to know Susan outside of Bret's idea of who she is in relation to him," she said.

Gerber's history with Murphy goes back to American Horror Story season 10, her first professional job, and she credits him with starting her career. She met Ellis separately, around when the novel came out, and by her own account walked up to him as a fan before either she or Murphy had any plans to work together on it. Four years later, Murphy called her mid-rehearsal for a play to offer her Susan.

What happens now depends entirely on FX. There's no season two announcement yet, and with the show barely a third of the way through Ellis's book, a renewal would need to cover a lot of ground fast. Gerber says she's already found herself protective of Susan, killer or not, and that the longer she played her, the harder it got to imagine turning on her. Whether the finale's whodunnit setup pays off with an actual reveal, or drags out the way the novel always meant to, is the only real cliffhanger left standing.