Leo the Leper and the Senseless World

In a society where people are sorted into castes based on which senses they don't have, sixteen-year-old Leo is in the lowest tier for being nose-blind, taste-blind, and partially numb. What's worse than being called a leper? The nonstop sensism is wearing him down. When researching for his history class about the plague that caused ninety percent of all people to lose at least one of their senses, he discovers a spot on a map where everyone is elite, unaffected.