Maile Meloy’s new novel, “Do Not Become Alarmed,” is, in a word, ambitious. The reader gleans this in the first two pages when the author introduces eight central characters, then proceeds to add another dozen or so as the deft plotting of this literary thriller unfolds like a journey through a maze in the dark.

The story begins with a Christmas cruise that two families embark on together from Southern California, heading off to the Panama Canal. There’s Liv and Benjamin and their two children, Penny and Sebastian, 11 and 8 respectively; and Nora, Liv’s cousin-almost-a-sister, and her husband, Raymond, and their two kids, Marcus and June, 11 and 6 respectively. The cruise is Liv’s idea for how to simplify the holiday, negate the pressure of getting together with in-laws, and help Nora cope with the emptiness of losing her mother to pancreatic cancer earlier that year.

It all starts carefree enough until the ship stops in Panama. Benjamin and Raymond go off to play golf with Gunther, an Argentinian they’ve befriended on the cruise. And Nora and Liv go off with their children, joined by Camila, Gunther’s wife, and her two teenagers, 15-year-old Hector and his younger sister Isabel. Pedro, a handsome, unflappable young crew member arranges to be their driver and guide for the day. When their van breaks down, Pedro confidently assures them it’s not a problem. There is a beach nearby where they can swim while waiting for another van to be delivered.

The kids take to the water on inner tubes, Liv and Camila imbibe a bit of alcoholic fruit drink that Pedro provides, and then both fall asleep on the beach. Pedro leads Nora into the jungle so he can show her some exotic birds.

Things take a terrible turn when an incoming tide carries the flotilla of frolicking kids up an intertidal river. Hector decides to swim back to the beach along the edge of the river where the current isn’t as strong to tell the mothers where they are. After he departs, the children become frightened, spying an alligator sunning on the far bank. They hear a car off through the bush and head for it. They come upon three people burying a body in a shallow grave. The children are forced by the gravediggers into their vehicle and taken deeper into the jungle to a mountainside enclosed compound.

Liv and Camila panic when they awake to find their children gone and start screaming. Nora and Pedro come running. Recriminations erupt immediately, Liv wanting to know what Nora and Pedro were doing in the jungle; Nora castigating Liv for not looking after the kids. Camila’s son, Hector, never appears to tell them what happened.

The tale splits here into two major storylines, one portraying the fear and hysteria of the grownups, shame and blame pervasive, and the other set in the compound where the children are held hostage by a narco clan. The older children seek to navigate the treacherous unpredictability of the group’s leader while also attending to the younger ones. A third storyline is interlaced, that of Noemi, a 10-year-old peasant girl from South America who is being driven north by a man she’s never met so she can eventually slip into the United States and join her undocumented parents in New York City.

Meloy peels layer after psychological layer away from the veneer of each of the grown-ups, probing their weaknesses and also the issues of infidelity, race, male posturing and female rage. At the same time, she explores the resiliency and resourcefulness of the children, especially the two eldest cousins, Penny and Marcus. They discern who they can trust at the compound and take daring risks to attempt gaining their freedom. Meanwhile, Noemi wins over her taciturn, mysterious guardian, learning the truth of his obligation to see to her welfare.

Award-winning author Maile Meloy lays confident claim to the thriller domain, expands it greatly, and makes it all her own. That she makes nearly a score of characters compelling and vividly memorable is reason enough to read this book. Meloy is a consummate storyteller, and “Do Not Become Alarmed” will grip readers to the end.

Frank O Smith is a Maine writer whose novel, “Dream Singer,” was named a Notable Book of the Year in Literary Fiction in 2014 by “Shelf Unbound,” an international review magazine. His novel was also a finalist for the Bellwether Prize “in support of a literature of social change.” Smith can be reached via his website:

frankosmithstories.com