A mysterious drowning in Oak Bluffs harbor and the poisoning of an Island matriarch in a dentist’s chair set the stage for Cynthia Riggs’s 13th novel, Bloodroot, the latest in her long-running series set on Martha’s Vineyard.

Bloodroot is lucky 13th novel in long-running series.

From sunsets over Sengekontacket Pond to the stone walls of Chilmark, nothing in the novel is too far removed from reality, and almost all of Ms. Riggs’s characters are derived from real people. The large cast includes an Oak Bluffs harbor worker, members of the Wampanoag Tribe of Gay Head (Aquinnah), a local police chief, and of course Victoria Trumbull, the 92-year-old amateur sleuth who never ages.

For a murder mystery, there are also many quiet moments in the woods or watching sunset, but this also speaks to the setting of this series, a quiet Island, where under the surface more turbulent waters boil.

The Vineyard itself is an ever-present character in the novel. Even passing moments remind us of where we are: “Rain beat against the window. Wind rattled the ancient panes. The lilac scratched the shingles.”

Driven mostly by dialogue, the story moves at a stead clip, with plot twists as quirky and unpredictable as the Island characters themselves. Along the way, readers get an inside glimpse of Island life — the bars, workplaces, waterfront properties and, most of all, the natural beauty that many of the characters, even those with bloody intentions, can appreciate.