Although the children are initially unaware of this fact, the scavenger hunt was designed to pursue the elusive duskwort. The fictional plant is a translucent moss that is extremely fragile. Even a small amount can put a person to sleep for a long time. Before Mr. Benedict was born, his parents tried to find duskwort so that they could use it to cure their narcolepsy. He later attempted to carry on his parents’ work, but he finds it almost impossible to locate duskwort because the plant is so similar to another plant called thwart-wort. Thwart-wort has no soporific qualities, and it is hardier than duskwort, so it tends to outcompete it. Mr. Benedict and Number Two finally locate what they believe to be duskwort on a remote island, and this is where they plan to meet the children at the end of their scavenger hunt. Unfortunately, the thwart-wort has destroyed any duskwort that may once have been on the island.

These plants connect to the theme of The Ambiguous Role of Deception, for although they look almost identical, they have different properties. Both Mr. Benedict and Mr. Curtain are seeking the plant, but they have unique reasons for their quests: Mr.