There’s something special about picking up a new book. One of my greatest pleasures when I was teaching was when my students weighed a book’s heft, cracked it open and inhaled that “new-book smell.” Then they scanned the front cover art and read the synopsis on the back cover. That’s “frisson.”

When I first picked up “The Spy on Putney Bridge,” by retired Col. David Fritz-Enz of Onchiota, I felt that same frisson of excitement. It is a solid, 370-page book, and I couldn’t wait to sit down with it. The problem with literally judging a book by its cover is that, sometimes, the reader is disappointed.

This story is about a World War II British soldier learning that his father, also a British soldier, and his grandmother were spies for Germany — interesting. Now, interweave conflicts like a forbidden romance between a young Austrian count and a young upper-class English lady–intriguing. Lastly, add historical context for storyline — riveting. This plot structure should provide a strong scaffold for the story-telling, so what went wrong?

I struggled with this question. My answer is, I think, that the historical structure of the book overwhelms the intricate storyline. The story begins in 1945, in London, with Charlotte Stetchworth confessing to her soldier grandson, Freddy, that she was a spy for the Germans in both World War I and II. Not only that, but her son Rags, Freddy’s father, was also a spy. Charlotte could be a sympathetic character: A young woman in love with a handsome Austrian count, she becomes entangled in his nationalistic goals rather than supporting her own country. But she seems petty and vindictive instead. Her ambition and resolute devotion to the man she loves and to their child should also render her a sympathetic character, but she seems more calculating than cautious, more vengeful than determined, and more self-righteous than morally driven.

In part two, Freddy disappears, and the story flashes back to 1915-1918, taking the reader through Rags’ military experiences. We find out that Charlotte takes Rags to Austria every summer since the year his English stepfather suddenly died. Rags spends the time with his biological father, the count, and his grandparents, learning how to speak German and getting to know his family. The author provides an excessive amount of historical context that bogs down this section of the novel, but here Rags could also be drawn as a sympathetic character. Groomed by his mother and father to become a true Austrian and to forsake his English heritage, what chance does the boy have to escape becoming a spy?

Part three covers 1936-1944, skipping almost two decades with no explanation for the omission. Rags has some wartime experiences that he seems to be mostly unaffected by, gets married and has two sons. Part 4, at 11 pages long, brings Freddy back in to the story. He figures out the mystery of the spy on Putney Bridge, his father, by talking to Rags’ commanding officer. The reader needs Freddy to tie up the loose ends, but I kept wondering throughout the novel why he was necessary. He didn’t really seem to have a significant role in the story.

One of the delights of reading good spy fiction is putting the subtle hints together and figuring out the resolution just near the end of the story. Looking back and saying, “Oh, right, I missed that clue,” is so much fun. There are some scandalous surprises throughout the story that kept me reading, but overall they don’t solve the structural problem of too much historical context and characters for whom it is difficult to feel sympathy. “The Spy on Putney Bridge” might work better as a straight-out history book rather than a historical novel. Yet avid readers of Col. Fitz-Enz’s nonfiction books would most likely enjoy this novel simply for its expansive coverage of British military history.