Alex Claremont-Diaz is the 21-year-old son of Ellen Claremont, the first female president of the United States. Alex is highly ambitious, with his sights set on a career in politics like his mother and his father, who is a US senator. Alex is finishing his last year of college and living in the White House with his family, including his older sister June. As the novel opens, June and Alex discuss the British royal wedding, which they are about to attend, and Alex talks about how much he hates the groom’s younger brother, Prince Henry. When Alex was 12, he used to look repeatedly at a photo of Henry from one of June’s teen magazines. But when he met Henry in person, Henry was rude to him, and he’s disliked Henry ever since. At the wedding, Alex is focused on Prince Henry and is irritated by everything he does, especially when he asks June to dance for a photo opportunity. Drunk, Alex confronts Henry for acting superior, and the two end up in a physical altercation that topples the $75,000 royal wedding cake. The international incident is a scandal, and Alex is forced to pretend to be Henry’s close friend to squash rumors of a shaky relationship between the United States and Britain. 

Alex has no choice but to go along with the plan. As Alex and Henry spend more time together, however, Alex is continually surprised by Henry and finds that Henry is not at all what he expected. He’s especially moved when he sees Henry speaking warmly and openly to a young girl with cancer. Before Alex can talk to Henry about it, there’s a loud noise like gunshots, and the two are rushed into a supply closet by security. In the closet, Henry ends up apologizing for mistreating Alex in the past and says he was cold to Alex because his father had just died. Alex and Henry exchange phone numbers and start texting and talking on the phone. The Claremont-Diaz clan has a family dinner, and Ellen offers both Alex and June positions in her reelection campaign. Alex is thrilled, but June, who wants to be a journalist, declines the offer. 

Alex, June, and their best friend Nora, who is the granddaughter of the Vice President, throw their annual New Year’s Eve party. Henry attends with his best friend Pez, who is enamored of June. Everyone is having fun together, but when Henry sees Alex and Nora kiss at midnight, he gets jealous and leaves the party. Alex finds him in the garden, and Henry kisses him for the first time. This spurs a crisis of sexual identity in Alex, who can’t stop thinking about the kiss. Though Alex has had a sexual relationship with his high school friend Liam and been attracted to men, he’s never considered himself bisexual. He talks to Nora about his confusion, and she says that Henry is gay, and that Alex seems to have feelings for Henry. When Henry flies in for a dinner, Alex kisses him while a security guard keeps watch. That night, they have sex for the first time, and Alex says they are friends with benefits. Henry and Alex continue to meet up to have sex when they can get away. They also begin to write flirtatious emails to each other and have heart-to-hearts on the phone. After a night on the town with June, Nora, Henry, Pez, and Henry’s sister Bea, Alex begins to develop feelings for Henry. 

Since Alex's mother is running for reelection and because Henry is a royal, it’s crucial that Henry and Alex’s relationship remain a secret. Alex often turns to his mentor and family friend, Senator Rafael Luna, for advice to help his mother with her campaign. It’s a blow to the whole family when Luna comes out as the running mate for Ellen’s opponent, Jeffrey Richards. Alex is devastated, and Henry comes to visit Alex at the Democratic National Convention to comfort him. The next morning, Zahra, Ellen’s chief of staff and family friend, catches Henry and Alex together and agrees to keep it a secret until after the convention. Alex comes out to his mother, who creates a PowerPoint presentation as a means of talking about the dangers of his relationship with Henry. She tells him she’ll support him, but he needs to be sure the relationship is forever. He goes to his family’s lake house with Henry, June, Nora, and his father Oscar. Alex comes out to his father, too, and he realizes that he is in love with Henry. Just as he’s about to tell Henry how he feels, Henry suddenly becomes formal and fake and leaves the conversation. The next morning Henry leaves the lake house without saying goodbye, leaving only a note. 

When Henry stops responding to Alex’s texts, Alex is distraught. He flies to London to confront Henry. Henry says he can’t be in a relationship with Alex because of the royal family. They have sex, and neither of them is sure whether it is a goodbye or the beginning of their relationship. Henry gives Alex his signet ring and says he wants to be with Alex. They are happy to be together, and they send each other passionate emails when they are apart.

Suspicions about their relationship start coming out in the press, so Alex and Henry pretend to go on dates with Nora and June. It’s painful for Henry to pretend to be someone he isn’t. Then, Akex and Henry's relationship is leaked to the press, with photos of them together and their entire email history. They are both forced to go on a communication blackout, and Ellen’s team attempts to triage the situation. Alex is miserable and worried about Henry. Eventually, he flies to London. Alex and Bea help Henry confront his family, including his grandmother, the Queen. As the Queen argues that the world will never accept them, a group of people gathers outside the palace to express support for Alex and Henry’s love.  

Nora, who has been missing since the news of Alex and Henry’s relationship broke, emerges and reveals that it was the Richards campaign that leaked their photographs and emails. Alex figures out that it was Luna who tipped them off. Alex talks to Luna, and Luna reveals that Richards sexually assaulted him when he was his intern. Luna joined the campaign to expose Richards as a sexual predator. Election night is tense, and in the end, whoever wins Texas, Ellen’s home state, will win the election. Ellen wins, and Henry joins Alex onstage for her victory lap. The two leave the party and go to Alex’s house. Alex shows Henry where he grew up, letting them in with the key he always wears around his neck.