Hugill Macauley is an organ-grinding monkey from a long line of organ-grinders. Since birth he has constantly been on the move with his family from country to country, living through great wars, poverty and trial as well as through grand adventures. Now, at an advanced age, Hugill goes on his last adventure to Africa in search of his roots and thus, he hopes, his final resting place. On this journey he makes the greatest of discoveries and wishes the world to know so he invites his dear old friend Grandfather Darwin of Leicester Square Underground (Piccadilly Line) to come and find him. After all, what better creature in the world would help him tell his story than his beloved and wise Grandfather Darwin?