ZERO DAY by David Baldacci main character John Puller is sent to investigate, but runs into roadblocks, first with civilian detective Samantha Cole, created on audio by narrator Orlagh Cassidy, (who plays off the main narrator, veteran Baldacci pro Ron McLarty). Cassidy sounds a little like Chief Johnson on The Closer, and her character ultimately flirts with Puller in banter and dialogue-exchange that's an efficient way of advancing the plot. Cassidy also voices other female characters, changing her inflection and tone to suit the occasion, thereby keeping any confusion from arising about who is speaking. With a dialogue-heavy text, it was a good choice to have two narrators, regardless of McLarty's skills, since it aids the book's "suspension of disbelief." On rare occasions sound effects are added for color, as when Puller is almost killed in an explosion. Is this a police procedural or a National Security related thriller? Well, both. The plot twists coming are not telegraphed, and a backstory involving Puller's Army hero father and convicted scientist brother round out an intriguing new addition to Baldacci's treasury.