Joyce-Armstrong is a pilot, whose allies dies while they are trying to break the current height record of 30,00 feet. The man is curious over the mysterious deaths and thinks that his friends have been caught in what he calls "air-jungles". Hay Connor and Myrtle are its two most recent casualties. Connor dies immediately after landing, while Myrtle is found beheaded. Joyce-Armstrong then decides to conduct his own investigation and takes his plane to a height of 40,000 feet. Who or what is killing the pilots? Will the brave aviator, Joyce-Armstrong, find the truth about the mysterious deaths? After take-off, can he safely return to the ground? What shocking discoveries will he make while in the air? "The Horror of the Heights" is a horror story by Sir Arthur Conan Doyle, first published in 1913