Anaya is a high school student plagued by severe allergies to nearly everything, which cause constant anxiety about her appearance. She relies on an inhaler and an EpiPen to survive daily life. Her physical limitations isolate her socially, but she remains highly observant. When a crisis hits her community, she is driven by a strong desire to help those around her.

Petra is an attractive high schooler who harbors aquagenic urticaria, an allergy to water that causes painful rashes. She lives in fear of losing her looks and social standing. She utilizes therapy techniques to manage her frequent anxiety. She misses her former passion for swimming and seeks unconventional treatments in secret.

Seth is an introverted teenager living with his eighth foster family on Salt Spring Island. He wears long sleeves to hide the scars covering his arms from a mysterious childhood surgery. Expecting eventual abandonment by his current foster parents, he keeps an emotional distance from others. He finds solace in his sketchbook and outdoor farm labor.

Michael is a botanist working for the Ministry of Agriculture with a specialization in invasive species. He involves his daughter in his scientific work and treats her as highly capable. His expertise becomes vital when unusual black grasses begin choking out the local ecosystem.

Dr. Weber is a physician and biochemist investigating a global biological threat. She approaches her subjects with empathy and open-mindedness, contrasting sharply with traditional military personnel. She seeks to understand the scientific anomalies surrounding the invasive plants rather than simply destroying them.

Lilah is a commercial pilot and Anaya's mother. She frequently encourages her daughter to view herself positively. Her career keeps her flying over the local islands, providing important aerial perspectives of the unfolding ecological event.

Diane is a local police officer and Petra's mother. Her law enforcement background makes her practical and strict. She focuses heavily on safety and preparation, reacting quickly to stockpile supplies when emergencies strike the island.

Petra's father is a nurse practitioner living on Salt Spring Island. He places strong faith in traditional medicine and relies on science. His strict medical views create tension when Petra seeks naturopathic remedies for her condition.

Mr. Antos is a farmer on Salt Spring Island who provides a stable foster home. He allows Seth independence and invites his participation in farm chores. He becomes deeply concerned about his livelihood when an aggressive black grass begins choking out his fields.

Mrs. Antos runs the farmhouse alongside her husband. She provides a warm environment with excellent meals for their foster children. As a caretaker, she handles the administrative realities of the social services system regarding Seth's placement.

Tereza is an older popular high school student who edits the school yearbook. She projects a mature image by smoking cigarettes and maintaining a steady relationship. She treats younger students with kindness.

Fleetwood is a high school student and Tereza's boyfriend. He assists with outdoor tasks on the school grounds. He leans toward conspiracy theories, guessing that foreign governments might be manipulating the weather.

Col. Pearson is a traditional military commander overseeing the response to the ecological crisis. He prefers weapons over scientific research. He views the unusual plants strictly as enemy targets that need to be destroyed quickly.

Ralph is a resident of Salt Spring Island known for entertaining conspiracy theories. He publicly voices suspicions that the government is covering up the true origins of the invasive plants.

Captain Brock is a pragmatic military operative tasked with moving through an eco-reserve. He relies on physical tools like chainsaws and conventional weapons to push through hostile environments.

Jolie serves as the second-in-command on a military extraction mission. She is a highly trained soldier who is quick to draw her weapon when she feels threatened by unknown variables in the field.

Mr. Hilborn is a high school gym teacher on Salt Spring Island. He maintains a skeptical attitude toward student warnings during an emergency on the athletic field.

Jen is a high school student who finds herself caught in the sudden environmental hazards appearing on the school grounds.