If you’re lucky, every once in a while you come across a book that overcomes you with its powerful story. “My Xanthi,” from first-time novelist Stephanie Cotsirilos, did that for me.

The novella is narrated by Nick Bolinas, a 66-year-old lawyer, paunchy and slightly balding, who is in private practice in suburban Riverside, California. A Greek-American, Nick lives with his wife Janet and their twin teenage daughters in a neighborhood with other Greek families, including many relatives.

One of the girls, Tess, is outraged that her father defends accused rapists and murderers. His wife, too, has strong opinions about many things. She’s feisty and not shy about challenging her husband when they disagree. Justice is a huge issue with Tess, who is attempting to write an essay about her father’s work. Justice is equally important to Nick. He is committed to ensuring that all individuals, no matter their crimes, receive competent legal representation.

Nick receives a packet of old letters from Greece, sent to him by Koula, the daughter of Xanthi, a woman who came to America to serve as a nanny when he was 4 and his mother was diagnosed with cancer. When she arrived at the train station in Chicago in 1954, dressed all in black, Xanthi spoke almost no English. “I am finally letting go of my mother’s letters,” Koula, now a mother herself, writes to Nick. “I think these letters should stay with you.”

The book shifts in time, relating the stories of Nick’s life in Riverside, his childhood under the firm but loving hand of Xanthi, and his reading of the letters she wrote at the time to her young daughter in Greece, whom she supported with her wages in America. The novella’s heart lies in the “packet of old letters (that) sits in my drawer like an unexploded incendiary device,” Nick states. “She raised me, taught me deeply, unconsciously… Xanthi prepared me to fight for even my most damaged defendants.”

One evening, when Nick’s parents are out, the boy wanders down to her room. Xanthi beckons him in, lifts him up on the bed, and then watches him sleep from a nearby chair. The two bond deeply during the dozen years she lived with Nick’s family.

Her letters home comment on the strange behaviors of Americans. “What I will never understand is the need for this substance you put under your arms to stop the smell of sweat. Americans have peculiar delusions of the nose… And the doctor they take me to, why does he insist a decent woman become naked? Shame.”

They relate her perspectives on the news, as when she laments over the murder of President Kennedy. “Kennedy’s death shocked the country, but it did not shock me,” she writes her daughter. “Though you and I have felt many such shadows pass over Greece,  I believe America is not yet fully under Lucifer’s dominion, though I have come to understand that black people here might disagree with me.”

Gradually, her letters turn to speak of their life in a small village after the and German occupation during the bloody Greek civil war that followed World War II. Fierce resentments raged among factions of villagers, between those who sympathized with the Germans and those who were loyal to Greece. Xanthi’s husband, it is revealed, was killed during the turbulence, a murder that she and her daughters witnessed, and a terrible fate befell one of her daughters.

Xantia’s moral core, her life experiences, even her outrage indelibly shape Nick. “How can I defend these people?” an adult Nick asks himself about his infamous clients. “Truth is… I do it every day in the teeth of doubt.”

“My Xanthi” has the moral heft of a much longer novel. Cotsirilos, who lives in Portland, nimbly weaves many elements, past and present, into the story. She brilliantly juxtaposes the commonplace with the horrors of war and the desire for retribution.

Frank O Smith is a Maine writer whose novel, “Dream Singer,” was a finalist for the Bellwether Prize. It was also named a Notable Book of the Year in Literary Fiction by Shelf Unbound. Smith can be reached via his website: www.frankosmithstories.com