Mr. Hoppy is a retired mechanic who lives alone in a tall, concrete apartment building. Missing the daily interactions of a workplace, he experiences intense loneliness that he manages by meticulously caring for a vibrant array of potted flowers on his balcony. He is an exceptionally shy man, entirely unable to vocalize his deep affection for his downstairs neighbor.

Mrs. Silver is a middle-aged widow who lives in the flat directly below Mr. Hoppy. She works part-time at a local candy and newspaper shop, keeping a pleasant but superficial rapport with her upstairs neighbor. She focuses nearly all her time and emotional energy on her small tortoise, continually worrying that his lack of physical growth makes him miserable.

Alfie is a small tortoise who has lived on Mrs. Silver's balcony for eleven years. Despite his age, he weighs a mere thirteen ounces. He lives in a custom-built winter house protected by wooden planks, regularly eating fresh meals and enjoying absolute devotion from his owner.