It has been almost 14 years since Ranger Anna Pigeon worked on Isle Royale (see Nevada Barr’s second book, A Superior Death), but this visit is different because she is going out in January rather than during the summer visitor season. Anna is now a ranger at Rocky Mountain National Park, and as wolves recolonize their historic range in the American west after years of protection under the Endangered Species Act, Anna’s superiors are developing a management plan for the recently delisted species. So Anna is sent to Isle Royale to learn how to run a wolf research and monitoring program from those who are currently conducting the world’s longest sustained study of wild wolves.

As the story begins, we learn that the Department of Homeland Security, seeking to seal the country’s northern border against any covert entry by terrorists, is assessing the possibility of opening Isle Royale year-round (currently, the island is only open to visitors from April through October). This is a problem for the island’s famed wolf-moose study because “winter study” is the time from January to March when researchers visit the island to determine population sizes for the two animals and to capture and radio-collar wolves, something more easily done without visitors on the ground annoyed at the intrusion on their wilderness experience. Additionally, winter is the time when the island reclaims its wild nature and wolves and moose are left to carry out their dance of life and death as they have for over half a century. In particular, it is the mating and denning time for wolves, a sensitive period that could be negatively impacted by a constant human presence. Consequently, DHS is looking to see if the wolf-moose study has learned all it can and if it should be shut down in the name of year-round recreational opportunities and increased border security.

Though the premise of the book is a little shaky, the mystery that unfolds is solidly engaging. There seems to be a new wolf on the island – DNA collected from wolf scat does not match any of the other individuals already living there. Moreover, this “alien wolf” seems to be unusually large as evidenced by tracks that the team finds, the brief glimpse of a silhouette Anna glimpses from the air, and the signs it leaves on dead wolves found by the winter study team. Finally, when one of the researchers goes missing, the concept of predator and prey takes on a whole new meaning, and Anna finds the remote island she once loved to be more claustrophobic than she remembers and more dangerous than she planned on.

The dark and sometimes cutting humor that Barr (a former National Park Service ranger) has bestowed on her alter ego in previous books is still here and just as funny. When Anna breaks through the ice on one of the inland lakes, she has to convince Bob Menechinn, the DHS agent, to save her rather than waiting for help to arrive from somewhere else. But Menechinn, who has proven to be incompetent outside of an office setting and something of a coward despite his macho act, is unmoved.

“Arguing a person past fear – particularly when they wouldn’t admit to being frightened – seldom worked, and Anna didn’t try to do it now. A tic started in her left thigh muscle above the knee, a flick of the skin the way a horse’s hide will flick to shake off flies.

‘I suppose I could just balance here till the ice refreezes along the seams,’ she said sarcastically.

‘How long do you think that would take?’ he asked seriously.

Anna was going to die and there would be no one but an oversized clown to witness her demise.”

Bob does eventually rescue her, and Anna struggles with her instinctual distrust of him as a result, but that struggle passes as she learns more about him. Later in the book, after Bob makes a rude remark to one of the researchers followed by a grin and a wink to Anna, she thinks to herself, “Having saved her life, he seemed to think he owned it. She wondered what he would look like with a plastic bag tied tightly over his head.”

When Anna finally puts the pieces together and learns the terrible truth behind the strange occurrences, the reader is hurtled toward the book’s jarring and fatal conclusion. Despite that, I found the last few pages a little disappointing, but perhaps stories, like life, are sometimes morally ambiguous and maybe loose ends are never neatly tied off.