Naturalist Diane Ackerman hosts this "Mystery of the Senses" installment of "Nova," which explores how the auditory sense guides and affects humans and animals in a variety of ways. Ackerman reveals how the human ear processes sounds and examines technology that allows the deaf to hear. The program also explores how hearing plays a role in mother-baby bonding, the Maori culture of New Zealand and the hunting life of the average owl.