Dear Wendy's follows Sophie and Jo, two aromantic and asexual college students who engage in an online feud while unknowingly becoming friends in real life. Sophie Chi, in her first year of college, runs an Instagram account offering relationship advice, known as ""Dear Wendy,"" while Joanna ""Jo"" Ephron creates the ""Sincerely Wanda"" account. As both accounts gain popularity, a rivalry ensues. Meanwhile, Jo struggles with existential crises over gender identity and fear of being forgotten by her few friends. Despite tensions online, Sophie and Jo grow closer in real life, discovering their shared aroace identity and starting a campus organization for a-spec students. The novel explores themes of friendship, identity, and acceptance as they navigate their college experiences and online personas, raising the question of whether their friendship will endure if they discover each other's online identities.