Family drama meets psychological thriller

Mary Kubica’s skill at melding the family drama with the psychological thriller takes another leap with “The Other Mrs.” A marriage and a family are on the verge of imploding. Add in the small population of an isolated Maine island that’s accessible only by ferry, and Kubica’s sixth novel evolves into a lockedroom mystery.

The move to the island is supposed to be a “fresh start” for emergency room physician Sadie Foust, her professor husband Will and their sons, Otto, 14, and Tate, 7. Back in Chicago, problems overwhelmed the Fousts — Otto was involved in a school incident that also ostracized Tate from his friends; Sadie made an almost career-ending decision; and then there was Will’s affair, which Sadie still hasn’t forgiven.

But this move is not without its own baggage. Will has inherited the house from his sister, Alice, who recently committed suicide. The inheritance stipulates that the couple assume guardianship of Alice’s very angry and sullen 16-year-old daughter, Imogen, who had discovered her mother’s body.

Imogen resents the Fousts and what she sees as their intrusion into her life, while she and Sadie take an instant dislike to each other. Sadie fears that her niece is violent and worries that her sons aren’t adjusting. Accustomed to the fast pace of an emergency room, Sadie is bored by her work at the small family clinic where she now works and is constantly at odds with the nurse and receptionist.

Tension ratchets up as Sadie’s distrust of Will palpitates throughout the household. She is sure he is going to cheat again. Sadie may not be wrong as Will’s exgirlfriend, Camille, appears to be stalking the family. A neighbor’s murder involves the Fousts, leading Sadie to suspect Will was having an affair with the woman.

Kubica effectively uses three narrators — Sadie, Camille and the mysterious Mouse — to keep the plot churning as she delves into the psychological motives of each character. The stakes rise because there are few ways to escape the island — the ferry runs only a few times during the day. Bad weather also can keep the residents trapped on the island, where gossip runs rampant and newcomers aren’t completely welcomed.

Secrets abound in “The Other Mrs.” as the plot moves at a brisk pace, with believable — and surprising — twists and a startling finale.

FICTION “The Other Mrs.” By Mary Kubica Park Row, 368 pages, $26.99