For two centuries, Quinton al-Zoubi, the Immortal Man, has been keeping the irradiated town of New Havilah alive, supplying the New Havilians with mushrooms, chocolate, tobacco, and, unbeknownst to them, the life-giving elixir Liphoric Zed. This life-weary rhythm is broken by the arrival of the mysterious Black Rot, a mould that has ravaged not only Quinton's mushrooms and chocolate but also his Flower-the source of Liphoric Zed. Can he stop it or will New Havilah perish like all the rest of humanity?