Summarize the novel.

Dave Robicheaux is a long-time resident of New Iberia, Louisiana who works for the New Iberia Parish Sheriff's Department. When Megan Flynn, a childhood acquaintance, returns to New Iberia, her presence inadvertently touches off a chain of events which leads Robicheaux on a quest to solve the old murder of Jack Flynn. Old tensions between blacks and whites, rich and poor, are unearthed and eventually exposed.