“Powers” uses a changing narrative form. The story begins in 1927, as Nancy, a young woman from a small Ontario town, writes in her diary about her life. Nancy likes to joke and flirt; she prides herself on her daring spirit, which she writes about with self-dramatizing flair. One day, while in town with friends, Nancy meets Tessa Netterby, a quiet, odd young woman with whom Nancy kept up “a sort of friendship” (270) after Tessa dropped out of school at age 14. Nancy hasn’t seen Tessa in a long time, but Tessa is still shy and reserved. Others laugh at Tessa and mock her for her supposed gift of premonition, but Nancy is intrigued.

Nancy writes about her fondness for jokes. Her attempt to play an April Fool’s prank on Wilf, a young doctor, involves feigning an illness and making him examine her. Wilf doesn’t find the joke funny, and Nancy must apologize to him. After trying to apologize to Wilf, Nancy is shocked when he proposes to her. Flustered, she accepts his proposal. Nancy doesn’t feel real love for Wilf, but she’s enthusiastic about the idea of a wedding. She writes about her surprise that her life might be so conventional.

The story switches to third-person narration. Nancy prepares for her wedding to Wilf, who grants her the freedom to organize the ceremony and then redecorate the house and attached offices from which he runs his practice. To help prepare for the wedding, Wilf invites his cousin Ollie to town. Ollie fascinates Nancy, as he seems to have traveled the world beyond the confines of the small town. His experiences include a long stay in a medical facility while being treated for tuberculosis. Keen to impress Ollie, Nancy introduces him to Tessa. The modest Tessa correctly guesses the items that Ollie has in his pocket, including a scrap of paper with writing on it. Ollie is suspicious. After they leave, however, Nancy notices that his experience with Tessa has changed him. She writes to Tessa to warn her against Ollie and what he might try to do. Tessa writes back, however, explaining that Ollie has proposed to marry her. They will travel to the United States, where Ollie thinks scientists will pay them handsomely to study Tessa’s powers.

The story moves forward to the 1960s. By this time, Ollie and Tessa have been gone from Nancy’s life for a long time. Nancy herself is much older, and she’s traveling through the US. She arrives at her destination: a medical facility that is about to be closed. Nancy received a letter from the people operating the facility: She was listed as a contact for Tessa, a patient at the facility. Nancy meets with the staff and insists that she wishes to treat Tessa properly. She learns that Tessa is one of the many patients who work at the hospital. In the intervening years, Tessa received electroshock treatment as a response to her apparent powers. This treatment dramatically affected her memory, and she doesn’t expect to ever leave the facility. She spends her time baking bread and cooking for the other patients. Meeting Nancy, Tessa struggles to remember what happened to her and Ollie. The money that he thought scientists would offer evidently didn’t materialize. Tessa correctly predicts that Nancy has no plans to take Tessa back to Canada. Nancy feels guilty. She promises to write to Tessa after she leaves, but doesn’t.

Years later, Nancy is a widow. She decides to travel and treats herself to a cruise. While returning from the cruise, she runs into Ollie in Vancouver. They catch up on their lives; Nancy informs Ollie of Wilf’s death, while Ollie seems to be struggling to get by. Ollie speaks about his time in the US with Tessa. The money he had hoped would be forthcoming from the scientists was not, as few academics could overcome the economic pressures of the era, as well as the complicated bureaucracies. The war decimated opportunities for legitimate research, so Ollie and Tessa were forced to use her powers differently. They performed in a traveling vaudeville act, and Ollie dressed up to assist in the performance. During this time, Tessa’s powers began to wane, and she had frequent migraines. Rather than relying on Tessa’s powers, they soon developed a system of signs and calls to trick the audience into believing that Tessa was performing psychic tricks. Ollie tells Nancy that Tessa died (which Nancy knows isn’t true, but she doesn’t challenge him). He tells her about his life since then: He took odd jobs up and down the Pacific Coast before settling on a small island. He does just enough to get by, he assures Nancy. Ollie accompanies Nancy back to her hotel. As they part, she feels an urge to say something to him and perhaps invite him to her room. Ollie preempts her, however, insisting that he must leave. Nancy departs, determined to track down Tessa.

Decades later, Nancy is an old woman. Her children believe that she now resides in her memories. When she sleeps, she dreams about a time when Tessa and Ollie were still together. She sees them in a motel, Tessa suffering from a terrible migraine. Tessa has a sudden mental image of a pyramid of dead flies behind the motel curtain. She peeks behind the curtain to find the pyramid of flies. The flies have been piled in this place by a person. Tessa is excited. She wakes Ollie, sharing her excitement that her powers have flickered back to life after being silent for so long. They hug and, as they touch, Ollie fears that Tessa’s reawakened powers will allow her to see into his pocket. In his pocket is an envelope, in which he has the documents to commit Tessa to a mental health facility, dooming her to a life in medical facilities like the one where Nancy found her. Tessa seems to sense these papers. Since she has lost any reason to care about her future, however, she says nothing. In Nancy’s dream, Ollie changes his mind about taking Tessa to the facility. Nancy is filled with a sudden, enlightening sense of reprieve as her consciousness seems to fall apart.