Neily Monroe is struggling to adjust to life following the murder of his ex-girlfriend Carly and the guilt he feels for not responding to her final attempts to reach him. Their breakup had been especially painful and embarrassing for Neily. When Carly’s cousin Audrey suggests the real killer is still at large, he thinks she is just trying to clear her father, who is serving time for the crime. Gradually, the two find clues in Carly’s diary that make someone else a plausible suspect. What had appeared to be a family tragedy triggered by a dispute over money now threatens to expose the darker side of an upscale and privileged clique. This is a sophisticated teen mystery, more introspective than action-oriented. Told as it is through the voices of both Neily and Audrey, readers get to know as much about the troubled girl they both loved as they do the principals. The adults are well drawn, and the impact of their unresolved issues intriguing. Less successful as a mystery than as a subtle look at family tensions and entitlement, at which it excels. (Mystery. 14 & up)