Nevada Barr's sixth mystery featuring protagonist Anna Pigeon descends
into a cave in the midst of Carlsbad Caverns to seek out the best place
for a murder. Pigeon's mental and detective skills are tested by her
claustrophobia as she rappels into a rescue effort for an injured
colleague. With every tortuous step Pigeon takes into the deep, the
tension increases as it becomes clear that more is at stake than just a
rescue effort. Classically, there is the shortest of lists of possible
suspects: as Anna herself realizes, it's unlikely that the convenient
tramp could find his or her way hundreds of feet underground. However,
Barr manages the restraints of the convention beautifully, and the
suspense remains taut until the perpetrator is revealed.