The book follows the life of Patrick Lewis, who is born in a rural logging town outside of Toronto called Depot Creek. He grows up with only his father, who works as a cattle herder on someone else’s land. His father is a quiet man, and Patrick lives an isolated life alone on the farm, becoming an astute observer of insects and small life around him. His father teaches himself the art of dynamiting, and he gets himself a job in the logging companies helping clear log jams in the rivers by dynamiting stuck logs. Patrick helps him every step of the way, and it is only after his father dies that Patrick leaves for the city of Toronto.
The chapter The Bridge is an in-depth look at the building of the Bloor Street Bridge through the workers’ eyes. During the construction of the bridge, a group of nuns gets lost in the night and accidentally ends up on the half-built bridge. There is a fierce wind, and one of the nuns gets blown off the bridge. Everyone believes she has died, but really she was caught in mid-air by a man named Nicholas Temelcoff, a Macedonian immigrant who performs the most daring work on the bridge. They slowly make their way back to safe ground, and he brings her to the local bar in his neighborhood. He has dislocated his arm catching her, but he falls asleep. When he wakes, he sees she has cut away her habit into a skirt, and left the black material there. He knows he will find her.
The first job Patrick gets in Toronto is as a “Searcher” for the missing millionaire Ambrose Small. He speaks with the millionaire’s mistress, Clara Dickens, and falls in love with her. They begin a love affair. Clara takes him to the country house of her friend Alice, where he meets Alice, then leaves the two women to go back to work. Soon Clara leaves Patrick for Ambrose, and even though Clara knows where Ambrose is hiding, she asks Patrick not to follow her. He doesn’t, forsaking the reward for finding Ambrose, and forsaking his love for her. Heart-broken, he takes up labor jobs in the city, living alone among immigrants and not speaking to anyone. Clara has left him only her pet iguana.
Alice shows up at his door almost three years after Clara has left, and finds Patrick still heart-broken over Clara. Alice tells him he has to heal himself of Clara. Patrick takes up work as a dynamiter to build the tunnel under Lake Ontario. He moves to a Macedonian immigrant community, and has to buy vetch to feed the iguana. He tries to explain his iguana to the shopkeepers and they gather around, friendly and eager to understand. When they finally understand what he’s been saying, he cries from the emotion of letting people into his lonely world. The Macedonians make friends with him and invite him to a gathering at the unfinished Waterworks building. There he watches a play that mimics the helplessness of the immigrants. He is so moved and terrified by the helplessness of the actress on the stage that he goes up to the stage to save her. It turns out to be Alice.
He and Alice begin a love affair and he moves in with Alice and her nine-year-old daughter, Hana. The father, Cato, was killed doing dangerous labor work, and Patrick becomes a surrogate father to Hana, eventually adopting her. They all live happily together for two years, and then Alice is killed by a suitcase bomb she accidentally picks up during a labor demonstration. Patrick is enraged by her death, and because Alice always believed that the rich exploited the poor laborers, he leaves Hana with Nicholas and goes to avenge Alice’s death by bombing the Muskoka Hotel, a place frequented by the wealthy of Toronto. He gets caught, and is imprisoned for five years.
In prison, he meets and becomes great friends with the thief, Caravaggio. Caravaggio and his wife Gianetta help Patrick with a scheme to blow up the Waterworks building, to get revenge on the rich Commissioner Harris, who envisioned the extravagant project without regard to how many lives of the laborers it took. Harris has taken to sleeping in his office of the Waterworks at this point. He had it built like a palace, with herringbone tiles in the bathroom. Patrick sneaks in through the water tunnel, Caravaggio and Gianetta had stolen a yacht and dropped him in the water with an air tank to do this.
Patrick hurts himself badly on the journey, by having to dynamite the screen at the end of the tunnel after he lost his wire-cutters underwater. He breaks into Harris’s bedroom/office and shows him the fuse-box that is rigged to blow up the waterworks. Patrick confronts Harris about his extravagance and his project that caused so many men to die building it. Harris knows he has to talk to Patrick until dawn breaks, when a guard will enter. He does this, and Patrick falls asleep. When the guard enters, Harris tells him to take the detonator away from Patrick and to get him medical attention. He lets Patrick go without prosecuting him.
When Patrick is home recuperating, Hana wakes him up and tells him there was a woman named Clara Dickens who called four hours ago, and Hana forgot to tell him. Clara has now called again, and said that she has been waiting outside in the cold by a phone booth for Patrick to call back. Clara is on the phone again now, and Patrick runs to get it. Clara tells him Ambrose has died and she asks Patrick to come to her. He says he will. He sleeps for one more hour, then asks Hana to wake him, so that they can drive together four hours north to Clara. Patrick says he will tell Hana on the drive who Clara is, and more stories of his and her mother’s life. This explains the italicized prologue that all of the stories in this novel are being told to a young girl on a drive in a car.