San Piedro, a small island in the Pacific Northwest, is home to salmon fishermen and strawberry farmers. It is also home to many Japanese-Americans. Snow Falling on Cedars opens in Judge Lew Fielding's courtroom as the trial of one of these Japanese-Americans, Kabuo Miyamoto, who is on trial for killing fellow fisherman Carl Heine, Jr., commences.
The story line of Kabuo's trial is the only one in Snow Falling on Cedars that is told in chronological order. Early testimony by the sheriff and his deputy provides the facts in the case: They were called to investigate the drifting of the Susan Marie, Carl's boat, and they found his body in his own fishing nets. Although the sheriff announced that Carl's death was an accident, everything didn't quite add up, so he got a warrant to search Kabuo's boat, the Islander, for the murder weapon. Finding blood on the butt end of Kabuo's fishing gaff, the sheriff arrested him.
As the trial progresses, the facts of Kabuo's case are revealed, as is the truth about what happened that night. Throughout the three-day trial, stories and history are told and retold from shifting perspectives and points of view; information is leaked slowly and deliberately, and two separate story lines develop in the form of memory and testimony.
The first major story line is the interracial love story. Kabuo's wife, Hatsue, shares a past with the island's only reporter, Ishmael Chambers. Their connection is established in the first chapter, but the extent of their involvement is revealed gradually. They grew up together, playing on the beach, looking for crabs, and shared a first kiss. Years later they kissed again, and a secret, teenage love affair blossomed. They didn't tell their families or their friends. At school they acted like strangers. Because of their cultural differences, they kept their interracial relationship hidden. During their senior year, Ishmael was certain he was falling more and more in love with Hatsue, while she was becoming more and more confused about her sense of responsibility to herself and her family. Before they could work through their feelings for one another, they were separated.
Hatsue and her family were sent to Manzanar, a World War II Japanese internment camp. There her mother found out about Hatsue's affair and pressured her into writing a "Dear John" letter. At Manzanar, Hatsue, determined to get on with her life, marries Kabuo.
After receiving the letter from Hatsue, Ishmael hates her, and he harbors this hate for years. During the war, he loses his arm, and his hate grows. After the war, he sees her around the island, with her children, and he is still bitter. He views the trial as his chance to get back in her life, no matter what the cost.
Besides providing the background to the interracial love story, memories and testimony also provide the story of an illegal land deal that was never completed. Carl Heine, Sr., agreed to sell seven acres of land to Zenhichi Miyamoto, Kabuo's father, in an agreement that sidestepped existing laws. This lease-to-own agreement lasted eight years. During the war, Carl Sr. died, and because of his internment, Zenhichi Miyamoto missed the last two payments. Carl's wife, Etta, who never approved of her husband's deal anyway, sold the land to Ole Jurgensen.
Kabuo visited both Ole Jurgensen and Etta Heine after the war, staking claim to the seven acres he refers to as his family's land. He even offered to buy it back, but Jurgensen isn't interested. Ten years later, after a stroke rendered him unable to work all of his land, Jurgensen put his farm up for sale. Carl junior stopped by right after the sign went up and made a deal to buy the land; earnest money changed hands. Later that same day, Kabuo stopped by and was devastated to learn that he arrived too late. Kabuo then approached Carl junior, asking him to sell the seven acres of land to him. Carl agreed to think about it.
At this point, toward the end of Kabuo's trial, the two separate story lines merge. For the most part, the interracial love story was private, whereas the quarrel over the land was more public. Clearly, Kabuo had both a motive and a method to kill Carl. Evidence places him at the scene of the crime, and he is also shown to be a liar.
The night before the end of the trial, Ishmael makes a discovery. While visiting the lighthouse for a story on the weather, he finds the notes from the night watchman that can clear Kabuo. Ishmael has to decide what to do: Does he keep the information to himself, use his newspaper to support Kabuo's case, and then work himself back into Hatsue's life while her husband is in jail, or does he reveal what he knows?
The end of the novel focuses on Ishmael's decision-making process and reveals exactly what happened on the night in question. The search for truth and justice comes to an end as Ishmael makes the morally and ethically correct decision to share his discovery. He also decides to make peace with Hatsue and get on with his life.