The Janus Stone
Elly Griffiths
Houghton Mifflin Harcourt, $25.

Sometimes a great first novel is no guarantee of a terrific second novel. I’m happy to report, though, that Elly Griffiths’ sophomore outing, "The Janus Stone," is more than a match for her wonderful debut, "The Crossing Places."

Her central character, archeologist Ruth Galloway, is still living on the edge of a salt marsh in Norfolk, a setting rich in archeological history dating back to the Iron Age. In this novel, the remains are slightly more recent: they are Roman, and some of the uncovered bones are more recent still.

Janus was a two-faced god, the god of doorways and openings, and the metaphor permeates the book in an offhand way. Early on the bones of a child are discovered at the base of an old arched entry, and while the doorway’s remains are ancient, the child’s bones appear to date only back to the 1960s.

Ruth is one of the more wonderful creations in recent mystery fiction. She’s unapologetically overweight, unapologetically single, doesn’t care about clothes or that she lives in an incredibly isolated spot. She is who she is.

Unfortunately for Ruth, part of who she is at the moment is pregnant with a married man’s baby, a thread left hanging open at the end of "The Crossing Places." The father is policeman Harry Nelson, whose marriage, while not blissful, is not miserable, and he has two daughters he loves very much. Ruth is stubbornly willing to go it alone.

Our book club read the first book, and the only criticism was that there were too few suspects. This is again the case, though I didn’t really care. Griffiths is very interested in character, and while she keeps her plot humming and doesn’t dilly dally, neither is she overly concerned with complications.

One of the other main characters in this book is a fellow archeologist, Max, who is shaded and complex and appears to have some secrets he’s keeping from Ruth. The big reveal as far as Max is concerned is one of the very well set up surprises of the story.

Griffith’s skillfully interweaves Ruth’s knowledge of archeology into the plot - making her a necessary expert the police need to consult — and she also weaves in history and in this case, Roman mythology. All of it is so seamlessly intertwined — character development, setting, and story line — that you won’t notice as you race through the book how fast you’re turning the pages.

Her sweet inclusion of life’s joys as well as the darker side of things puts her on a par with an author like Louise Penny, who tells a rousing, sometimes darkly shaded story, but leaves the reader refreshed and happy at the end of things.

I’m happy to report that there’s a third Ruth Galloway novel due in January, making the New Year already something to look forward to.

Robin Agnew is the co-owner of Aunt Agatha's Mystery Bookshop in Ann Arbor.