The following version of this book was used to create this study guide: Schwab, Victoria. Our Dark Duet. Greenwillow Books, 2017.

Kate Harker hunted monsters in Prosperity. She returned to her new friend Riley’s apartment, where she had been living for the past six months. She hid her identity from her new group of friends called the Wardens, not wanting them to know that she was the daughter of Callum Harker, the notorious, recently deceased leader of North City in Verity.

In Verity, August Flynn, a Sunai, used his violin to steal the souls of North City residents trying to find refuge in South City from the monsters. As a leader in the FTF, run by his adoptive father Henry Flynn, August reaped the soul of a refugee who confessed to being a killer. He felt conflicted after the kill. He thought about his adoptive brother Leo, whom he had killed six months ago for betraying the FTF. Meanwhile, Sloan, the Malchai who usurped Kate’s father for control over the monsters in North City, killed a girl who looked like Kate out of hatred. Alice, a new Malchai who had been born from a murder Kate had committed, gave him patches from dead FTF soldiers’ uniforms and an explosive.

In Prosperity, Kate went monster hunting the following night. A new monster called Chaos Eater took control of her mind. Kate returned to Riley’s apartment feeling strange as the monster continued to haunt her mind. In Verity, August and Rez, his FTF partner, went to investigate a missing squad in North City. They found the soldiers dead and were attacked by Sloan’s supporters, called the Fangs. August played his violin to stop them, but they were still able to kill Rez. August killed them and then killed the Malchai that were born from the murders. Alice followed August and taunted him about the deaths. She sent Malchai to attack him, which August killed as well. By the time he reached the Seam to return to South City, he was drenched in blood.

The Chaos Eater gave Kate violent urges throughout the day. She accessed the monster’s thoughts and realized that it was in Verity. She decided to return to Verity. She reached North City and locked herself in a building to protect herself from the monsters. Meanwhile, Sloan enlisted human engineers to help him invade the FTF Compound. Kate ran into Soro, a Sunai who wanted to kill her since her soul was stained red. August found them and saved Kate. He brought her to the Compound, where Soro questioned her about the new monster she had found. August spoke to Kate and let her stay in his room.

In the morning, Kate broke out of August’s room and spoke with Henry Flynn about the Chaos Eater. She learned that Henry was sick. She convinced him to let her join the FTF. Kate trained with an FTF squad. Ilsa sent Kate videos of August killing people for the FTF over the past six months. Kate asked August about it, since she had seen that he had changed much over this time. They went to hunt the Chaos Eater together as it targeted an FTF squad. August brought a soldier that the monster had possessed to a cell in the Compound. He confessed to Kate about how he had changed who he was to serve the FTF. They kissed, but August worried that he would reap her soul. The next day, Kate looked through the records on the FTF server and confronted Henry about why they have not planned an attack on Sloan in the past six months. She felt a sudden urge of violence and ran away. Meanwhile, Sloan and Alice captured the Chaos Eater.

Soro noticed the monster had infected Kate and locked her in a cell. Then the power went out in the Compound and Kate escaped. She decided to help defend the FTF from Sloan’s invasion. She saw Alice for the first time and realized that the Malchai was her creation. After the attack, Kate and August spoke on the roof. August left her, but, when he returned, she had gone chasing after Alice. August, Henry, and the Alpha squad searched for Kate in North City. Sloan attacked Kate. The Alpha squad arrived to save Kate, but Sloan and Henry disappeared. Sloan sent the FTF a message that showed him holding Henry captive in Kate’s father’s old penthouse.

Kate, August, Emily, and the Alpha squad found Henry in the penthouse while Sloan set the Chaos Eater loose in the Compound. The monster forced the FTF soldiers to attack each other. Kate stayed behind in the penthouse to fight Alice while the rest rushed back to the Compound. August found Ilsa and helped her kill Sloan. Ilsa used her powers to kill the Chaos Eater, which destroyed her too. August returned to the penthouse to find Kate had killed Alice, but Kate was bleeding out and died in his arms.