If John Steinbeck had written Animal Dreams, we'd encounter Hallie sitting under a tree—or maybe a large cactus—in Tucson, discussing Marx with the children of the neighborhood. She's the perfect heroine of socially conscious fiction: a charismatic giant of a woman, with a set of deep commitments that will lead her on a dangerous and ultimately tragic adventure.
But Hallie's not the hero here.
As it is, we meet her in a Toyota pickup truck, saying goodbye to her sister as she heads off on her journey south—and out of the primary narrative of Animal Dreams. We'll never talk to her again. The only dialogue we get from Hallie after she and Codi part ways is in Doc's memory and in the letters she sends to Codi from the commune.
Still, even though Hallie is never physically present, she is a huge presence in this novel. Primarily, that's through her influence on her older sister Codi. It's fair to say that Hallie is Codi's favorite person ever.
The opening scene, for example, shows the two sisters asleep in Codi's bed as little girls, with Codi curled protectively around Hallie. Codi's first lines in the novel describe their almost physical dependence on one another. Codi admires Hallie—she's tough, smart, she can moonwalk, she always pays her library fines, and she's deeply committed to her principles. Hallie seems blessed to Codi, like a tree that bears "radiant bushels" while everything around it is just surviving (5.102).
The one thing you can definitely say for Hallie is that she knows who she is: she's a plant-loving, Spanish-speaking, refugee-supporting activist who is looking for a movement she can devote her life to. Codi remembers Hallie once weeping because "there might never be a cause worth risking everything for in our lifetime" (4.73), so it makes sense that Hallie doesn't feel like a hero for going down to Nicaragua to support the Sandinistas. She's just grateful that there's a place where her knowledge of plants can make a real difference to people. She's tired of just helping American gardeners out with their suburban slug wars.
At the same time, like Loyd, Hallie's already developed identity exempts her from the primary struggle confronting the rest of her family. Doc and Codi need to figure out who they are—and in Doc's case, often where he is and what year it is. Hallie already knows all that. She's more developed than her older sister and her father that way, and this might be why this novel is less focused on her story.
Hallie's life in Nicaragua seems pretty idyllic, except for the constant threat of violence from U.S.-funded counterrevolutionaries, of course. We learn that she's giving lectures on farming, that she's got a crush on a schoolteacher named José, and that she wants to stay in Nicaragua forever. We also learn that her memory's better than Codi's: she remembers the flood, for example, while Codi has completely forgotten it.
That said, a funny thing happens to Hallie's character over the course of the book: we almost seem to know her less and less as the novel progresses. Loyd doesn't even remember what she looks like in Chapter 18, and he says, as they're watching the Pueblo dances in Santa Rosalia, that Hallie "never finished getting born" (18.46), because her mother died in childhood. Codi herself agrees.
We've got to wonder what Hallie herself would think of the idea that she's not a complete person, but we never get to. She's kidnapped before Codi can dispatch another letter. It kind of makes you wonder: are the Noline sisters really like two people who share an organ, as Codi says? Can only one of them have a full identity at a time?
Or is Hallie's progressively smaller personality and presence a function of the way that the novel is filtered through Codi's consciousness, so that as Codi's own identity develops, the shadow of Hallie's seems to fade?
In the end, we get a tribute to Hallie's life and identity at her funeral, where Codi tells us a lot about her sister, like the fact that she loved Paul Simon, and that she believed reading helps you become "a protagonist of history" (26.11). We get the feeling that just as Hallie didn't see herself as a hero, she wouldn't see her death as a tragedy—just the end of a life well lived.