The Brook originates from a mountainous source inhabited by water birds and flows through forests and hills, passing thirty slopes and over four dozen bridges on its way to a small town. It touches grassy lawns and forget-me-not flowers before joining a larger river near Phillip's farm. Tennyson uses exquisite language to convey the brook's musical sounds and movements through foliage and fields as it travels, as well as its reflection of sunlight and moonlight off its banks. The poem compares the brook's permanence to human impermanence.