To their classmates in the Waiākea High School class of 1995, they were The Triplets—an insular trio of self-absorbed girls who graduated summa cum laude in condescension. Decades later and several years apart, two of them vanish under identical circumstances from a desolate stretch of asphalt called the Saddle Road. The remaining Triplet then seeks Hawaiian PI Noelani Lee's help to find out what happened to her friends.

Once a target of their cruel taunts, Noelani swallows her pride and takes the case, beginning with the second Triplet's unfinished true-crime podcast—in which she was on the verge of identifying the person responsible for her friend's earlier disappearance. At the same time, Noelani is frustrated at her failure to track down a larcenous funeral home director, the defendant in a multi-million-dollar malpractice lawsuit. But when he's found bludgeoned to death in his home, Noelani soon unspools links between his xenophobic Hawaiian separatist group, the two missing women, a questionable real estate deal, and an illegal adoption ring.

As she explores the unfulfilled adult lives of all three Triplets, Noelani confronts a case paved with barefaced bigotry, long-buried secrets, and brazen denial, all as she questions the meaning of loyalty and friendship—and comes to grips with her own unhappy past.