Penny is a gaunt, dark-haired young girl evacuated from the city during the Blitz. Intelligent and observant, she forms a quick bond with Primrose during their frightening train journey. She carries a serious demeanor that reflects the emotional weight of leaving her family behind for an unknown rural destination.

Primrose is a plump, blonde child who evacuates the city alongside Penny. Anxious about the journey, she copes with the terrifying reality of wartime separation by inventing creative scenarios in her head. She relies heavily on her vivid imagination to process the sudden disruptions in her young life.

A terrifying creature of local legend that roams the woods near the children's temporary housing. It possesses a bulbous head with a triangular mask, thin lips frozen in anguish, and a massive body composed of decaying organic matter and man-made trash. It leaves a trail of destruction, bloody slime, and the overwhelming smell of rot wherever it slithers.

Alys is a very young, cherubic evacuee with blonde curly hair and light blue eyes. Considerably smaller than Penny and Primrose, she desires their companionship and tries to tag along on their unauthorized excursion into the strange woods.

Penny's mother is a frightened woman attempting to protect her daughter from the bombings of the Blitz. She sends Penny away to the countryside, finding herself entirely unable to articulate the realities of the war or the sudden necessity of their separation.

Primrose's mother is an attractive woman who makes the difficult choice to send her daughter away to keep her safe from city bombings. She provides Primrose with handcrafted stuffed animals, doing her best to preserve a fraction of her daughter's childhood innocence during a frightening time.

Penny's father is an older man working in the Auxiliary Fire Service in London. He faces the intense dangers of the Blitz directly, fighting the fires that threaten the city while serving as a brave, stabilizing presence in his daughter's mind.

Primrose's father serves in the military during the war, working aboard a troop carrier. His extended absence requires his family to adjust to sudden realities while he faces the immediate dangers of the conflict at sea.