Ledroptha lived in an old Dutch orphanage in the center of Amsterdam together with his brother Nicholas. As young boys everyone thought that Nicholas would become a genius and would be the one to be very successful, Nicholas moved to the USA.
Mr. Curtain built very powerful turbines which would eventually be sold on to from the government. Mr. Curtain is the infamous creator of the menacing Whisperer, which somewhat controls people's minds (although a more appropriate phrase would be that The Whisperer sends messages that disorient the truth from peoples minds and give them an illusion of something like The Emergency) and has power over their memories. Mr. Curtain, like his brother, has a bad case of narcolepsy. Narcolepsy is a condition that causes you to fall asleep when you experience strong emotions such as fright, strong happiness, laughter, anger, and strong sadness.
Mr. Curtain's full name may be viewed as a pun, as in "Le-DROP-tha(THE) CURTAIN."
In the Mysterious Benedict society, Mr. Curtain (otherwise known as Ledroptha Curtain) had a machine called the Whisperer. This machine was used to control people's minds and that's why the Mysterious Benedict Society comes to the rescue.
The Perilous Journey
Mr. Curtain's brother, Nicholas Benedict finds out about an extremely rare plant—duskwort (translucidus somniferum)—that may cure his narcolepsy. It is so rare that it is considered extinct, but Mr. Benedict's and Mr. Curtain's parents, found living specimens of the plant, in an undisclosed location. Mr. Benedict and his assistant, the pencil like Number Two, go off in search of the plant, and the island. They are captured by Mr. Curtain, who also wants the plant. He, however, does not know where the plant is, and only knows the island that it is on.
After Mr. Benedict's capture, Reynard "Reynie" Muldoon, Kate Wetherall, George "Sticky" Washington, and Constance Contraire go to his aid. They are later accompanied by Kate's father Milligan. After following a series of clues, the children find Mr. Curtain on an isolated island in a cave, pretending to by Mr. Benedict, chained to a stalagmite. His prisoner, Mr. Benedict, is chained to Mr. Curtain's wheelchair. The purpose of it was for the children to "free" Mr. Curtain. However, Reynie notices that it is Mr. Curtain. Nevertheless, all four children are chained, including Mr. Benedict, by Mr. Curtain's assistant SQ Pedalian.
Mr. Curtain soon obtains the location of the duskwort, which is an iridescent moss that grows on the stalactites and glows in the dark. This information is obtained at the agreement that he would not harm the children, However, when the children, Milligan, Mr. Benedict, and Number Two are back in Mr. Benedict's house, it is revealed that there is no duskwort- it was completely destroyed by a similar, but more powerful species. Mr. Curtain does not find a cure for his own narcolepsy.