The leading lady talks to ET about the final episodes of the supernatural drama, which she warns is an absolute 'roller-coaster.'
Freeform's fantasy drama kicks off its final 12 episodes on Monday, nearly one year after it was last on TV, with a mother of a cliffhanger to solve: Is Clary Fray (McNamara) actually dead? While we'll have to wait for Shadowhunters to return in a few short days to have that question answered (our guess is a big, fat N-O), McNamara is assuring fans that the upcoming episodes are well worth the wait -- and may even be the show's best yet.
"What I love so much about [season] 3B is the show is really settled into itself. It’s so rich and everyone’s so firmly rooted in their characters. We’ve created this universe and it lives and it breathes as its own organism now and it’s so fun to see it all come together," McNamara told ET at the Disney-ABC party at the Television Critics Association press tour earlier this month. "It being the final 12 episodes, we all poured our heart and soul into it and they are our best episodes, in my opinion."
McNamara, who is also appearing on The CW's Arrow as Oliver and Felicity's daughter Mia Smoak, spilled nary a secret for what's to come for Clary and company, but offered this intriguing tease: What you think you know isn't what you thought at all.
"You really get to see these characters turn on their heads. You see the story, you see the characters go to a place that you would have never expected. Everything that you think you’re sure of, everything that you think is solid is not and it’s ripped away and turned upside down and thrown for a loop," the 23-year-old actress hinted. "You really see these characters really have to fight and struggle."
Speaking more specifically to Clary's unclear fate at the start of the upcoming run (is she dead? is she something other than dead?), McNamara shared that the surviving characters open the season believing their fearless leader is no longer among them, which, as she tells it, reveals as much into their psyche as anything else.
"Right now, Clary’s dead so you see each of the characters grieving and dealing with the loss of her, which is not something we’ve seen or thought you would see. It reveals different facets of the characters that you haven’t seen before," she said. "What happened to Clary is unclear, as you saw in [the midseason finale]. She could be dead, it could be worse than death -- whatever has happened to her. You really don’t know at this point, but it will definitely force her to confront things that she’s trying to push away. She’s trying to push away this Morgenstern that’s a part of her, this family connection that she’s fought against and this mess that her parents left behind. She’s forced to confront all of these things in this upcoming season and it’ll be interesting to see who she leans on to deal with all of that."
It's been a minute since McNamara and her co-stars, which include Dominic Sherwood (Jace), Harry Shum Jr. (Magnus), Isaiah Mustafa (Luke) and Alberto Rosende (Simon) -- all of whom will appear live with ET Online for a spoiler-filled chat on Thursday, wrapped filming on Shadowhunters. McNamara was both reflective and excited about reliving the final hours of Clary's story.
"It’s bittersweet, but the way [co-showrunners] Todd [Slavkin] and Darren [Swimmer] wrote the finale is also bittersweet. It’s very fitting," McNamara mused, confessing that it took her a moment to come around to how Shadowhunters wraps up. "When I first read the ending, I wasn’t 100 percent sure about it but having watched it and seen how the season goes together as a whole, it’s perfect in my opinion. It is the best ending that it could have been and I’m proud of it. We got to be creative for ourselves and we got to make this for us; it’s a love letter to the fans."
Asked whether Clary's ending aligned with her own personal thoughts and desires for the character she's played since 2015, McNamara said it wasn't where she thought the heroine's journey would go. But, she noted, memorable surprises are often born out of the unexpected.
"It wasn’t what I expected and I don’t think anyone will expect it," she teased. "When I watched it, there are things that the camera picked up on that I didn’t even know I was doing. And the person I was in the scene with, I didn’t even clock that they were doing that either. It creates this ending that really is a question mark and it really is bittersweet. It’s open for interpretation and I’m very excited to see what people have to say."
"The door is left open and it’ll be open for the fandom to interpret it as they will and discuss as they will, which is what they’ve done from Day 1," McNamara said of the series' swan song, airing May 13, "and it’s why I love them so much."
As for the fast-approaching Shadowhunters return, McNamara promises a plethora of Easter eggs for fans of Cassandra Clare's popular Mortal Instruments novels, on which the show is based, as well as viewers of the show unfamiliar with the books' plot twists.
"For book fans, you will see some of the favorite book moments that we haven’t done yet. For show fans, you will see these characters struggle. It’s a roller-coaster," she previewed. "You’ll see the most romantic moments, you’ll see the happiest you’ve seen these characters and you will see these characters fighting to survive, fighting for their relationships, fighting for each other and fighting for the world itself to survive. It’s a battle to the finish from beginning to end. It’s darker than it’s ever been, it’s bloodier than it’s ever been, the stakes are higher. It really is a push to taking that next step farther and I think it accomplishes the task."
Shadowhunters premieres its final episodes Monday, Feb. 25 at 8 p.m. ET/PT on Freeform.
'Shadowhunters' Star Katherine McNamara Teases Lots of 'Easter Eggs' for 'Mortal Instruments' Fans