Zoey is a curious young girl with a strong interest in science and the natural world. She wears overalls with a cat patch, mismatched socks, and lab safety goggles on her head that she calls Thinking Goggles. When her mother leaves for a conference, Zoey takes on the responsibility of caring for injured magical animals that visit their barn. She uses the scientific method to test hypotheses, running practical experiments to figure out how to help the creatures.

Sassafras is Zoey’s intelligent feline companion. He provides comfort when Zoey is stressed and actively participates in her scientific experiments. Unlike regular pets, Sassafras can see the magical creatures that visit the property, easily befriending them and keeping them warm.

Zoey's mom is a dedicated scientist who fosters her daughter's interest in the natural world. As a child, she discovered that magical creatures live in the forest and require care. She leaves Zoey in charge of the magical animal barn while she travels for a week-long academic conference.

Zoey's dad is a thoughtful, home-based caregiver who makes animal-shaped pancakes and saves small fish for the family cat. Unlike his wife and daughter, he cannot see magical animals. He readily offers practical advice when Zoey struggles with her science experiments, helping her troubleshoot without understanding the full magical context.

Marshmallow is a small, scaly, green baby dragon who seeks help at the barn. Initially weak and cold, he becomes the primary subject of Zoey's scientific experiments as she tries to determine his dietary needs and temperature requirements.

Pip is a bright purple frog with orange spots who introduced Zoey's mom to the hidden world of magical forest creatures. After Zoey's mom nursed him back to health years ago, he installed a magical doorbell on the barn so other hurt animals could find her.

Sophie is Zoey's friend who owns a pet lizard. Her specific instructions about leaving her lizard's tank heater on help Zoey understand how to care for cold-blooded creatures.