With many drawings and lots of conversation, Jack and his friends explore the garden and countryside near where they live. They discover all kinds of seeds, nuts, eggs and plants, learning lots about how nature works. They are amazed to discover that big fruits like melons originate from tiny seeds that can sit in the palm of a person's hand. The many fruits that people eat day to day, such as apples and pears, grow from trees that sprouted many years ago from a tiny seed that was made inside one of its fruits.

Later on in the book, Jack and company find out how birds and other creatures hatch from eggs. Sometimes the eggs are protected by the mothers who lay them, while other eggs are simply left in the sun's warmth to hatch after a short time. The gang also find out how bumblebees make more plants grow by spreading pollen that they pick up while eating nectar from flowers.