The Marquis de Carabas, a self-made legend and resident of the London Underbelow, wakes up from death to find his magical coat missing. He starts his search for his prized possession in the Below's foodcourt, where he gets information from one of the Mushroom folk in exchange for a promised delivery of a love letter. The Marquis then recruits a guide to take him to the Shepherd's Bush, where his coat is supposedly hidden. Unfortunately for the legend, the guide turns out to be an agent for his enemy, the Elephant, and he's captured and sentenced to death. Before he dies again, the Marquis is saved by his older brother and first rival Peregrine, who disappears as soon as they escape. The Marquis continues to the Shepherd's Bush alone, where he is brainwashed and made a member of the flock. Unbeknownst to the Marquis, his brother had actually been following him and tries to save him again. Before he can snap his younger sibling out of his trance, the brothers get caught, along with the Elephant, who also fell prey to the Shepherd while trying to get his revenge on the Marquis. When confronted with the Shepherd, who is wearing the Marquis's coat, the Marquis eventually regains consciousness and saves them via the love letter he was tasked to deliver, which was filled with magical mushroom spores that take over the Shepherd's mind. The three escape and part ways. The Marquis, reunited with his coat and come to terms with the separate but similar powers of him and Peregrine, delivers the letter and disappears into the night, just like how his brother always disappears.