“My son is dead,” 96-year-old Cassandra MacCallum says halfway through Merilyn Simonds’s artful and allusive new novel. It is a declaration, not a lamentation, one called forth by the unexpected and unwelcome appearance in her life of a young Burmese woman claiming that the son in question survived the crash of his plane in Burma during the Second World War. “A Pho Charlie O’Brien,” she tells Cass, “he my grandfather. Your son.”

Cass is understandably skeptical. The emails from “Miss Nang Aung Myaing” read like a generic internet scam: “Please I have very suffered to come your country. I contact now to prove my blood. Please you help.” The messages keep coming, though, and when Nang adds, “I have present you from A Pho Charlie,” Cass can’t resist replying: “What do you have?” Before long she is watching Nang row across the strait to the small island off Newbliss, Ontario, that is Cass’s final refuge.

Nang’s arrival prompts Cass to reminisce about her eventful life. Fortunate to have had a father who nurtured her scientific curiosity, Cass trained as a nurse, then took her skills to Mexico, where one of her patients was a young girl named Frida Kahlo. While in Mexico, Cass also took up photography, which became a lifelong passion and perhaps provides an implicit model for Simonds’s own technique in the novel: “She gave herself up to it, to the art and science of pinning a split second in its place.”

Later, in New York, Cass worked with a doctor who was trying to develop a polio vaccine to counter the epidemic ravaging the city. At Children’s Memorial Hospital in Montreal, Cass researched infants’ emotions, including their ability to feel pain. In the meantime, Cass’s sister May remained at the family farm in Ontario. It is from there that Cass’s son ran away to join the Royal Canadian Air Force, to fight and – so his mother has always believed – die in the war.

Though Simonds depicts these varied settings and incidents with adept and vivid specificity, the overall effect is somewhat miscellaneous. It’s only Cass herself – sharp, determined, cantankerous – who provides unity to the narrative. Refuge interweaves Cass’s painful reckoning with her family history and her developing relationship with Nang. Cass’s suspicions about Nang persist, but the longer Nang stays on the island the more entangled their lives and feelings become and the more Cass’s defensive crust erodes.

Whatever the facts about the past, Nang represents an opportunity for something authentic to develop in the present. Cass must ultimately consider whether human connections, whatever their pretext, are more meaningful than blood ties. It is a moving conclusion to her fitful and often unhappy story.