AN UNMARKED GRAVE. By Charles Todd. Harper Collins. 262 pages. $25.

It is the spring of 1918, and the Spanish Influenza spreads across the globe. The insidious killer spares no one. Hidden among the victims of the battlefield and the pandemic, nursing sister Bess Crawford discovers the body of a murder victim.

In order to solve the mystery, however, Crawford must survive the influenza herself, cross the English Channel several times, travel to Cornwall and Wales, drive across the war-torn French countryside and experience several close calls.

Charles Todd is the pseudonym of the mother and son writing team responsible for the Inspector Ian Rankin series as well as the Bess Crawford mysteries. The historical setting they create for “An Unmarked Grave” is richly textured and well-developed. They show an England coming to grips with modern warfare.

Crawford is a strong and immensely likable character embodying the changing role of women during the war years.

The plot, however, is a mixed bag. “An Unmarked Grave” possesses enough plot twists and red herrings to hold the reader’s interest, but it’s flawed.

The authors’ reliance on a series of convenient coincidences to solve the mystery cheapens the solution.

“An Unmarked Grave” fails to measure up to the standards that fans of the “Todds” have come to expect.

Reviewer Teri New, a writer based in Charleston