DEATH'S DOOR: 7th Billy Boyle World War II Mystery from James R. Benn

Considering that the United States only took part in World War II for three years, James R. Benn is doing a fantastic job at packing an entire series of mysteries into the timeline. The seventh of the Billy Boyle investigations -- rich, lively, exciting, and tautly plotted -- opens in February 1944, as the Irish-American police officer recruited to assist "Uncle Ike" in Europe is juggling a mix of fear and resentment: His beloved, Diana Seaton, a special agent also working for the Allies, has reportedly been captured by the Gestapo and is being held in Rome.

And not only is Billy unable to get there, and unsure of whether Diana is alive -- he's being ordered back to England.

Luckily, by the third chapter, Billy and his close friend Kaz -- that is, Lieutenant (and Baron) Piotr Augustus Kazimierz, of the Polish Army in Exile -- have found a way to turn their backs on home and move toward Rome, where the power politics of the Vatican and the Gestapo together create a level of threat equal to, maybe even exceeding, what's come their way in earlier volumes.

Benn's dexterity with his battles-and-brigades timeline runs much deeper than a tale of war coupled with detection (Billy's role). He enriches the novel with the growth and changes of Billy and Kaz's friendship, as well as their pursuit of Diana's whereabouts and hoped-for safety. Diana's role as an agent also makes this series especially enjoyable, as she navigates the line between being Billy's lover and being a strong and savvy agent able to choose her own risks.

Most of all, Benn pushes both Billy Boyle's curiosity and our own, along with sometimes unsettling observations in the casual voices of the two friends. After Billy and Kaz search for details and truth from some of the Vatican's finest, they talk over what they've unearthed:

"Interesting," Kaz said after May had left. "Two men, Brackett and May, in the same circumstances. One retreats inward, not daring to take any chances. The other seems to thrive, rising about the situation he finds himself in."

"You never know about a guy," I said. "Before the war, Brackett was probably a big shot, and May a servant. War, even if it isn't a shooting war, puts pressure on everyone. Some can take it, others can't. There's no predicting." I looked at Kaz, who'd been a skinny student before the war. He probably never thought he'd go near a gun or harm anyone. Now he was a scar-faced killer -- wiry, wary, and strong.

"No," Kaz agreed. "Life is strange, Billy. It is why I have come to appreciate it."

DEATH'S DOOR goes onto my re-read shelf because of this willingness to explore character and change. Benn's not just taking us through the war -- he's taking us through the formation of people's inner selves. Loyalty, integrity, and courage all demand testing. I found myself cheering for Billy precisely because of the way he handles those testing moments.

How many more Billy Boyle mysteries will there be? I'm sure James Benn has it planned -- but don't tell me. I'm enjoying the suspense from book to book. I'm also appreciating Benn's ability to surprise me with intriguing details of the war, and to keep the war itself suspenseful -- even though we believe we know how that part will eventually end.