The novel follows Anastacya Mikhailov, a princess with the magical ability to control blood who searches for her father's killer after being framed for his murder.

Prior to its publication by Delacorte Press, Blood Heir was subject to controversy due to allegations of racial insensitivity and other issues.

When she was a young girl, her powers resulted in the accidental deaths of eight people at an outdoor market in the capital city of Salskoff, causing rumors to spread about a vicious "blood witch".

Ramson and Ana track May to the Playpen, a nightclub in the city of Novo Minsk where Affinites are forced to perform for entertainment and are secretly trafficked.

In the palace's throne room, Ana discovers Morganya and Luka, who is planning to abdicate due to his poor health.

Luka announces that he will cede the throne to Ana instead, but he is killed by the imperial advisor Sadov, Morganya's ally.

While Morganya assumes the throne, Tetsyev helps Ana fake her death by giving her a paralysis poison.

Ana and Ramson escape the palace dungeons with the help of imperial guards who secretly oppose Morganya.

Ana informs Ramson that she plans to travel south to find Yuri and the Redcloaks and join the rebellion against Morganya.

Her proposed fantasy trilogy, described as "Anastasia meets Six of Crows", sold at auction to Delacorte, reportedly for a high six-figure deal.

Kat Rosenfield of Vulture wrote that on social media, Zhao was "an enthusiastic, effective communicator who was deeply engaged with issues of diversity and knew how to make herself heard".

[2][6] In January 2019, however, some social media users accused the book of racial insensitivity and other issues, causing Zhao to postpone its release until November.

The controversy was covered by journalists Jesse Singal in Tablet and Kat Rosenfield in Vulture, as well as publications such as Slate, The New York Times, and The New Yorker.

[3][4] Rosenfield said that the Twitter user "declined to offer proof" of Zhao's behavior,[4] while Singal found no evidence to support the claims.

Editor Krista Marino stated that they "worked to further establish the nuances of indentured labor and trafficking within this fantasy world, without changing major plot points".