Clarke is a caring friend and a ruthless killer. Photo: Cate Cameron/CW

As a lover of sci-fi, YA, and female characters with personalities beyond “love interest,” I often find myself trying, and failing, to sell people on the CW’s postapocalyptic drama The 100, which returns for its third season tonight. The show is admittedly silly-sounding: 97 years after a nuclear holocaust, 100 juvenile offenders are sent down from a dying space station, the Ark, to see if Earth is inhabitable again. It’s BSG with teens!

Unfortunately, those who disregard it are missing out on not just a surprisingly deep take on the moral calculus of survival, but also sci-fi’s best teen protagonist in a long while: Clarke Griffin. The blonde-haired, blue-eyed Clarke, played by Eliza Taylor, initially presents as a classic teen heroine — kind, smart, brave, loved — akin to the young women populating the forgotten graveyard of teen TV, including The Secret Circle’s Cassie Blake, Star-Crossed’s Emery, and the titular character of The Nine Lives of Chloe King. (More enduring, only marginally less one-dimensional examples include Heroes’ Claire and The Vampire Diaries’ Elena.) But Clarke resists such easy classification. She’s a caring friend, a charismatic leader, and a ruthless killer, defined not by her gender but by her circumstances.

Within the first few minutes of the pilot, Clarke’s mom provides a helpful character description to set viewer expectations: “Your instincts will tell you to take care of everybody else first.” Clarke proves that statement true as soon as the 100 reach the ground. She attempts to find food, prevent the others from removing the wristbands that connect them to the Ark, and keep everyone safe from the not-as-dead-as-anticipated inhabitants of the surface (nicknamed Grounders). The other characters sarcastically refer to her as “Princess” and complain about her inability to chill out, man.

And yet she’s not the Goody Two-shoes you’d expect: She doesn’t waste time pontificating about the right thing to do, and focuses instead on finding the most effective way to achieve her aims. She doesn’t hesitate to kill, and even torture, when she feels it’s necessary. Clarke wants to be good, but she’s smart enough to realize that may not be an option if she wants to survive.

By the end of the first season, the rest of the 100 are taking their cues from her, and she remains the de facto leader even after the grown-ups make it down to the surface. Of course, her assumption of that role is possible in part because none of the other characters are concerned by the idea of a woman in charge. (Her bisexuality goes similarly un-commented on.) Scarcity-driven societies with perfect gender equality are a common feature in YA science fiction that often feels profoundly out of touch with reality. Here, though, the writers have taken advantage of their futuristic setting to tell a radically different kind of story about a young woman — one in which she consciously takes responsibility for her society’s survival. Unlike similar characters, like Divergent’s Tris and The Hunger Games’ Katniss (or, for that matter, BSG’s Laura Roslin), Clarke isn’t genetically blessed or forced into leadership; she chooses to lead, because she’s good at it.

But even more remarkable is how she leads, with her head rather than her heart. When young women are in charge on TV, they tend to make bad decisions out of a desire to do the right thing or protect a loved one. Daenerys is a classic example of this trope: She excels at inspiring others, but she’s terrible at thinking ahead — the few strategic moves she makes are suggested by her male advisers. Characters like Korra and Buffy fall into the “chosen one” archetype: They may make fewer tactical errors, but they also spend a lot of time chafing at the responsibilities forced upon them. All three live by basic principles of right and wrong, good and evil.

Clarke, meanwhile, is purely pragmatic, which makes her a brilliant strategist. She analyzes every situation to determine how to twist it to her advantage, and she never appeals to anyone’s better nature unless she thinks it’s the most effective way to manipulate them. (In that sense, she’s actually more similar to Tyrion than Daenerys.) Caught up in the ongoing wars on the ground, she’s forced to contend with what price she’s willing to pay for her people’s survival. Will she sacrifice one life? What about dozens? What about children? At every turn, she makes the smart call — sacrificing the boy she loves to build a desperately needed alliance, letting a town be bombed to prevent the enemy from knowing she has a spy — regardless of the cost. “I did what I had to do” is her constant refrain. Ultimately, this philosophy leads Clarke to an act of genocide: murdering the entire population of her enemies’ mountain home, children included.

As the new season picks up, we find Clarke in more complicated ethical terrain, struggling with the horror of her own choices, allowed neither the easy forgiveness nor the redemptive death most of TV’s morally compromised heroes (of any gender or age) receive. Her massacre at the mountain has made her a legend among the Grounders, who now call her “Wanheda,” a.k.a. the Commander of Death, and leaders of the various factions are looking to use the power that title confers for their own ends. Despite her misgivings, Clarke soon uses the mantle to her advantage, as both a tool and threat.

Given her actions, it’s tempting to view her as an antihero, but doing so would be a disservice to the moral complexity of her character. Antiheroes are fundamentally selfish; Clarke is not. Her concern for others is what drives her to each terrible act, and in a less brutal world, she might well have turned out more like Buffy — in this one, Clakre has no such luxury. And in a TV genre where most young women are still stuck taking orders from men, the girl is leagues ahead.