The first section of the book is called "Bonds," which is set in the 1920s and follows a couple named Benjamin and Helen Rask. Benjamin is a very wealthy tycoon (who was born into money) whose seemingly singular focus is amassing a larger fortune. Although Benjamin is successful, he is also very callous and rude. But his relationship with Helen is incredibly successful because they both enjoy being alone (and not spending much time with each other). After the Stock Market Crash of 1929, Helen's mental health takes a nosedive, and she is forced into a sanitarium. Helen starts therapy with Doctor Frahm, a man who Benjamin grows to dislike because he is unwilling to provide the details of his sessions with Helen to Benjamin. Benjamin grows increasingly frustrated and uses his money to fire Dr. Frahm and hire Dr. Aftus, who employs convulsion therapy—which is also called electroconvulsive therapy. But after Helen undergoes convulsion therapy, she has a heart attack and dies, upsetting Benjamin but allowing him to return to New York to pursue his business endeavors.
The second section of the book is called "My Life," and is the first-person biography of a man named Andrew Bevel, who was close to Helen and Benjamin Rask. In this section of the book, Bevel reveals how he played a part in the 1929 Stock Market Crash and his relationship with Helen and Benjamin, who he reveals is based on a couple in his life named Mildred and Howard Vanner. Bevel is fascinated with the Vanners and decides to write about Mildred (Helen), who felt that she was misunderstood. He talks about Mildred's interests, her mental illness, and her philanthropic efforts—among many other things.
The third section of the book is called "A Memoir, Remembered," which is told from the perspective of Ida Partenza, who was formerly employed by Andrew Bevel. One day, Partenza decides to visit her former employer's mansion, which she discovers has been turned into a large and fantastical museum. The museum, in fact, houses Bevel's personal documents—documents which are no doubt personally interesting to many across the world. And it was Partenza, in fact, who helped Bevel write his biography, which was covered in the previous section of Trust. "A Memoir, Remembered," is fundamentally an exploration of Partenza's relationship with Bevel, who she grew to admire despite taking a job with him to pay off her debt. She developed a voice for Bevel which allowed him to continue his business pursuits, but she was still perplexed by Bevel's relationship with the aforementioned Mildred. Finally, at the end of her visit to her former employer's mansion, she finds Mildred's hidden personal diary.
In the fourth and final section of the novel, entitled "Futures," Mildred writes in the first person about her experiences in the hospital in the days before her death. The fourth section, as it turns out, is Mildred's diary. As she grows older and increasingly unable to take care of herself, Mildred channels her energy into the diary, which she uses to regain a sense of independence. In her diary, Mildred lets readers know that she was Andrew's closest confidant and was largely responsible for his financial success. And it was Mildred who discovered an issue with the stock market in 1929, which allowed him to profit greatly from the great stock market crash.
