 Professor Henry Kleeblatt, a former biophysicist, trapped in a mental institution, believes that plants can talk. In order to prove that his theory is correct, he builds the Sound Machine, an instrument which can capture high pitched sound waves such as those of plants and converts them into sounds that the human ear can hear. Over the course of the movie we get an inside look at how Kleeblatt s mind works. Through his perspective we see his brief hallucinatory episodes he experiences while he struggles to achieve his goals. The only person who Kleeblatt trusts and openly communicates with is nurse Yolanda. Although she has her own reservations about his ideas, she has developed a soft spot for him and does all she can to support and encourage him. She eventually sets up a meeting with Kleeblatt and the clinic s doctors to give him a chance to prove his theory. As Kleeblatt works vigorously to complete his invention, various technical and emotional problems slowly drive him to the brink of insanity. Sound Machine is a depiction of one man s battle with external and internal demons. Kleeblatt s faith in his machine and his belief in the capacity for plants to communicate with humans is a source of inspiration for Yolanda who befriends him. Still, his beliefs don t coincide with popular social and scientific views and thus Kleeblatt is ultimately persecuted for the action he has taken to support his ideas.