Mira is the 29-year-old founder of Birnam Wood, a grassroots guerrilla gardening collective in New Zealand. Charismatic and passionate, she thrives on being the center of attention and leading her organization toward ambitious goals. She frequently bends rules, steals equipment, and ignores minor ethical boundaries, justifying her actions as necessary for the greater good of her environmental mission.

Shelley is Mira's roommate and the practical backbone of Birnam Wood. While Mira provides the vision, Shelley handles the day-to-day operations, paperwork, and social media. Quietly exhausted by living in Mira's shadow, Shelley harbors deep, growing resentments and actively considers ways to sabotage their friendship to free herself from the organization.

Tony is a founding member of Birnam Wood who recently returned to New Zealand. Raised in a wealthy family, he is acutely self-conscious about his privilege and overcompensates by dressing poorly and strictly adhering to his political ideals. He aspires to be a famous investigative journalist but struggles with self-righteousness, frequently alienating his peers during debates.

Lemoine is an American billionaire venture capitalist and the CEO of Autonomo, a drone manufacturing company. He presents himself to the Darvishes as a doomsday prepper buying land for a bunker, but his true goals involve secret resource extraction in the national park. Cold, calculated, and heavily reliant on surveillance technology, he enjoys manipulating people through the information he steals from their devices.

Sir Owen is a wealthy New Zealand businessman who built his fortune through Darvish Pest Control before his wife inherited a large parcel of land in Thorndike. Recently knighted, he enjoys his new status but feels a sense of national inferiority when dealing with the American billionaire Robert Lemoine. He is generally likable and deeply devoted to his wife.

Lady Jill is the independently wealthy wife of Sir Owen and the legal owner of the Thorndike farm. She has a sharp mind for business and quietly believes that men are generally inferior and require coddling. While she loves her husband deeply, her ambition leads her to orchestrate business maneuvers behind his back to secure advantageous deals.

Amber is a member of Birnam Wood and a manager at the cafe where the group holds its meetings. She is sensitive to group dynamics and protective of her ego, requiring Shelley to publicly appease her online to keep the peace.

Veronica is Tony Gallo's sister. She has a contentious but supportive relationship with her brother, frequently calling him out on his behavior while still providing practical help when he needs it.

Rosie is a young woman who connects with Tony after his return to New Zealand. She is impressed by his ambition to become an investigative reporter, though she soon finds herself entangled in the suspicious silence surrounding his disappearance.