NOTE: This study guide refers to the Kindle Edition of The Water Knife, published May 26, 2015.

The Water Knife takes place in a near-future United States, where the southwestern states compete with each other for access to a reliable water supply during a period of extended and disastrous drought.

The novel is related in the past tense from a third-person omniscient narrator and alternates between focusing on the perspectives of its three central characters: Angel, Lucy, and Maria. Angel Velasquez is the “water knife” of the novel’s title. He worked as an undercover agent for the state of Nevada, infiltrating and sabotaging the water supplies of rival states. At the start of the novel, Angel had been sent to Phoenix, Arizona, by his boss Catherine Case to investigate some mysterious incidents in the city.

Lucy Monroe, a journalist, was living in Phoenix. After discovering that her friend Jamie had been murdered after he became involved in a shady scheme to sell water rights, she feared that Jamie’s killers would come after her next. Maria, a teenage refugee from the evacuated state of Texas, was living in Phoenix with her best friend Sarah. After a business scheme to sell water at a construction site went wrong, Maria and Sarah found themselves in debt to a local gangster known as The Vet.

When Angel arrived in Phoenix he met up with his colleague Julio who explained that one of his contacts in the Phoenix Water Board had been brutally murdered. The two men went to the morgue where they met journalist Lucy Monroe who was investigating the death of someone who had been tortured in a similar way to Julio’s colleague. Angel felt a powerful connection with Lucy which motivated him to let her leave even though she might have had information that he needed.

Lucy discovered that her friend Jamie had been doing business with a man named Michael Ratan, who lived in a luxurious apartment building called the Taiyang Arcology in Phoenix. Meanwhile, Maria and Sarah decided to have sex with Ratan so that he would pay them enough money to cover their rent and escape the wrath of The Vet. The morning after the girls slept with Ratan, two men broke into Ratan’s apartment, murdering Ratan and Sarah while Maria hid under the bed. Lucy came to the apartment while the men were still there and they kidnapped her. Angel arrived and interrogated Maria about what had happened to Lucy. Angel let Maria keep a book that she had found in Ratan’s apartment.

Following clues given to him by Maria, Angel realized that his colleague Julio was double-crossing him and had kidnapped Lucy. Angel tracked him down and saved Lucy from being tortured. Angel and Lucy shared what they knew about the water rights Jamie and Michael Ratan had been trying to sell. Lucy and Angel hid together in a Phoenix slum, during which time a sexual/romantic relationship began between the pair.

Lucy continued trying to investigate the mysterious water rights but was intercepted by agents from California who threatened to kill Lucy’s sister Anna and her children if Lucy didn’t agree to betray Angel and turn him over to California. Lucy led Angel into an ambush at a gas station, but he escaped. A group of disgruntled and mistreated Texan refugees became involved in the fight, having mistaken Lucy and Angel for fellow Texans, leading to a fire which quickly spread across the whole of Phoenix. Using the Texans and the fire as cover from the Californians, Lucy tracked down the wounded Angel and saved his life.

Angel realized that his boss Catherine Case had ordered his murder because she mistakenly believed he had stolen the water rights. Case agreed that she would let Angel live if he found the rights and brought them to Nevada. Angel realized that the rights were tucked inside the book that Maria had taken from Ratan’s apartment.

Angel and Lucy found Maria in Carver City, where she was trying to cross the state border. Maria needed to escape Arizona because The Vet was going to kill her after she failed to pay him the money she owed. Angel told Maria that if she gave him the water rights he would take her to live in Las Vegas, where she would be safe. When Lucy read the water rights she realized that they could save Phoenix from being destroyed, so she decided to take the documents back to Arizona despite the suffering this would cause for Angel. Unwilling to lose her one chance to escape Arizona, Maria shot Lucy, allowing Angel to regain possession of the water rights. Maria sat on the riverbank listening to helicopters approaching which would take all three of them to Nevada.