Thicker than Water is a short story written by L. J. Smith. The tale centers around Keller and her soulmate Galen Drache, during the final battle between the Nightworld and the Wild Powers. The story is told by Keller herself in first-person narration.
"This story is about what happens to Keller and some of the other Night World characters during the night when the Apocalypse finally comes about. You don’t need to have read Strange Fate to understand it—which is a good thing since Strange Fate hasn’t been published yet."
The four Wild Powers have set out to accomplish their mission to save the world from the end of days. Keller, now 18 years old and living in Harmony, a town established by Thierry Descouedres as a sanctuary for Circle Daybreak, with a special Tower headquarters below ground, has been nominated as Last Resort for Iliana, her blood-sister, but Keller and Galen (now engaged) have no choice but to remain behind while the Witch Child fights. Keller explains who she is and reminisces on Iliana, in particular the girl's selflessness and genuine love for all people. It is also revealed that Iliana was placed in cryogenic sleep until she was needed for the final battle.
Keller goes on to explain her role as Last Resort, after going through the hierarchy of Circle Daybreak; the Last Resort is the person nominated to save a designated person or target when all else has failed. Meaning, should Iliana's guardians, bodyguards and escorts fail, she must go in and pull Iliana out of whatever danger she is in (being a shapeshifter prince, Galen was prohibited from gaining this position himself). However, the Nightworld had managed to awaken every single dragon laid to rest since prehistoric times, the mass of which then proceeded to lay waste to the world (San Francisco and Paris are mentioned as being obliterated). Although not confirmed, because Iliana had been in Paris during the attack, she may have been killed.
Devastated by the prospect of Iliana's possible death, rather than stay with Galen for comfort, she gives in to her urge to go hunting, changing into a panther and going to stalk in the attached park, although Galen is worried for her. Having completed a sprint without killing, Keller decides to return to her soulmate, but she runs into a lamia in the park. Although recognizing him as Whitcombe, one of Thierry's men, Keller impulsively dislikes him and is disturbed when he begins scratching her ears. Returning to her clothes, Keller sees they have been destroyed, and finally realizes she is alone with Whitcombe, who has killed the keeper and guards. Whitcombe reveals himself as a tri-horned dragon, and Keller fights against him, sending a message to Galen along the silver cord as a warning to the residents of Harmony; she adds that she loved him, at the end of her brief relay.
Planning for only a few moments, Keller climbs a nearby oak tree and leaps on top of the dragon, with the intent to "bite the horns off". The dragon resists, but doesn't yell out (not wanting to draw attention); using Power and tossing his head, Whitcombe flings the tenacious Keller from him, resulting in broken ribs for the panther fighter. Although Keller has damaged one horn, it is still attached to the dragon's head. Remembering her loved ones, and that even Alex, Iliana's brother, is in the city, Keller lunged for Whitcombe again and, climbing up his body with her claws, makes it to his forehead and finally succeeds in breaking the damaged horn in two. Before Whitcombe can throw her again and despite the agony generated by Power being thrown down her throat, Keller is able to chomp down and take off a second horn. The next toss removes Keller, who impacts with a tree, breaking her leg. She again uses the silver cord, and Galen responds, telling her they're "here", while a second telepathic voice tells Keller to remain still.
Blearily, Keller sees what she believes is her human self (Rashel Jordan) throwing shuriken stars at the dragon's eye. At the same time, she sees a "compact" male vampire, Quinn, attack the dragon, insisting that Keller run as he bites the third horn, taking out the dragon's eye in the process. The dragon, now in too much pain to care for subtlety, tries to incinerate them. Keller, gathering her strength, climbs the dragon a final time and goes for the last horn; Thierry also arrives and insists the other allow her the "honor" of killing Whitcombe. She is successful, and, supported by Galen, she resumes human form and is taken to the infirmary.
Keller awakens in the infirmary with Galen beside her; he informs her that she fought the dragon despite Quinn's report that she was "almost dead". He also tells her that a few other dragons had been found, but there is no word on the status of Iliana. Commenting on Quinn and Rashel saving her, Keller then notices Rashel is in a nearby bed as well, being watched over by her own soulmate. It is here that Keller begins to notice how many similarities the two young women have in common, along with appearance. Rashel admits to being the first one to respond to Keller's summons, who in turn reported it to Quinn, insisting on going to Keller's aid. This surprises Keller, as Rashel is human, and had been ruled out as a lost witch, her being able to telepathically hear Keller a mystery.
Here, Galen and Quinn ask basic information from Rashel and Keller; it is clear they have a suspicion regarding their soulmates. Galen tells the others about how Keller was abandoned as a baby, and Quinn draws forth a letter Rashel had found a little before joining Circle Daybreak, addressed from her father to her mother, Melisande Jordan; Rashel had always assumed her father had been a Marine who had died overseas.
The letter describes Rashel's father as leaving the family, with their "darling little misfit" (a possible second child), and how he feels conflicted regarding how Melisande truly sees him. As such, he decides to leave her and return to his "own people". Intrigued, Keller asks for the letter; when placed with her own note left with her as a child, which she had always kept since, the letter and the note match together perfectly. It is deduced that in fact, Keller's father, a shapeshifter and Melisande Jordan's husband, had taken Keller, born in a half-and-half form, and abandoned her, unable to cope with being unable to shapeshift for his family's safety, as well as the shame having a shapehshifter husband and daughter might have brought upon his wife. Rashel and Keller are in fact fraternal twin sisters, explaining how Rashel could hear Keller's mental call.
The two sisters are elated at the revelation, with Rashel even wondering if she can change form, when Thierry enters the ward. He returns the pendant Iliana had given Keller to her; Keller notes that he must be hurting too, as Hannah had been with Iliana in Paris. Kissing Keller's forehead in gratitude, she realizes Thierry knew about Rashel being her twin all along. After Thierry departs, prompted by Quinn, the twins begin having a friendly argument over who is the elder of them.
- Rashel's status as fully human might be disputable with the revelations uncovered in this story.
- In the Night World, twins appear to have a natural telepathic bond, as shown with Poppy and Phillip North, and now with Rashel and Keller.
- Other than Rashel, Galen is the only other person to call Quinn by his first name, John.