The Boundary of Life is Quietly Crossed is the first film in a trilogy exploring the evolving cultural and scientific significance of the human heart. It tells this story through four narratives: the earliest effort to visualize the pulse; the EKG and EEG of a young woman in love, which were placed aboard two space probes now heading into interstellar space; the earliest attempts to photograph the pulse; and current efforts to design a “beatless” artificial heart—a physiological solution that has never existed in human evolutionary history.