Cyrus is an Iranian American man in his 20s who lives near the fictional Keady University in Indiana. He moved from Iran with his father Ali when he was still a baby and has since become Americanized in many ways, although he remains curious about his Iranian heritage. Both Cyrus and Ali believe that Cyrus’s mother, Roya, was killed on Iran Air Flight 655, which a U.S. warship shot down during the Iran-Iraq War.
Around the time he first goes to college, Cyrus starts drinking heavily, eventually getting into cigarettes and drugs as well. His addictions take over his life, getting in the way of his poetry-writing, although a bright spot is that he meets Zee, his eventual roommate and best friend—and perhaps something more.
After joining Alcoholics Anonymous and getting sober, Cyrus struggles to fill the void in his life. He becomes obsessed with learning about martyrs and decides to write a whole book of martyrs, believing that their stories hold the key to living a meaningful life. Cyrus even considers the possibility of trying to turn himself into a martyr. One day, Cyrus’s friend Sad James hears about an unusual art installation at the Brooklyn Museum and encourages Cyrus to check it out. It’s called Death-Speak and is about a performance artist named Orkideh who is dying of cancer but has refused treatment, instead vowing to live out her remaining time in public at the museum. Cyrus decides to go speak to her in person, and Zee agrees to come with him and split a hotel room.
When Cyrus meets Orkideh at the Brooklyn Museum, the two of them are immediately fascinated by each other. Cyrus explains his martyrdom project, and Orkideh helps him understand how his fascination with martyrs is typical of Iranian men. She helps Cyrus realize that he is specifically interested in so-called earth martyrs who die for an earthly cause instead of a religious one. Cyrus keeps coming back day after day to continue his conversation with Orkideh.
The novel jumps around in time, often showing different characters’ perspectives. Cyrus’s uncle Arash, for example, remembers growing up with Roya in Iran, ultimately becoming a soldier in the Iran-Iraq War who had the unusual task of riding out on battlefields at night among the dying and pretending to be an angel. Perhaps the most substantial other character is Roya, who comes to feel out of place in her traditional role as an Iranian wife. She realizes that she has romantic feelings for her friend Leila, and together, the two of them start a relationship behind their husbands’ backs.
When Leila’s husband catches her cheating, she has to flee the country. She uses Roya’s paperwork, and it turns out that it is actually Leila who dies on Flight 655, not Roya. Roya uses her supposed death to start a new life in the United States, collaborating with and eventually marrying (for a time) the gallerist Sang Linh, taking on the name Orkideh.
Now, in the present timeline, when Cyrus goes to see Orkideh for another conversation, he finds that she has died, seemingly of suicide. He is shocked and doesn’t know how to feel. It is only later, when talking to Sang, that he gets confirmation of something that he had begun to suspect: that Orkideh was actually his mother Roya.
In talking more with Sang, Cyrus comes to realize how his book of martyrs project is ultimately about trying to fill a void in his life and that there might be other ways to achieve that. He realizes, for example, that he has taken for granted the love of Zee, who has always been there for Cyrus but whom Cyrus recently argued with. In a surreal, possibly dreamlike, final moment in Prospect Park, Zee and Cyrus make up and each confess their love for each other. Cyrus walks toward a pool of golden light and reaches out for a hand that might be Zee’s or might be his own.
The book’s coda is a joyful scene from years earlier, when Roya and Sang celebrate a successful gallery show by Roya (as Orkideh) and prepare to ship the art away to its new owners.