Fablehaven: Rise of the Evening Star is the second installment in the Fablehaven Series.
At the end of the school year Kendra and her brother Seth, find themselves racing back to Fablehaven, a refuge for mythical and magical creatures. Grandpa Sorenson invites three specialists-a potion master, a collector of magical relics, and a trapper of mystical creatures-to help protect the property from the Society of the Evening Star, an ancient organization determined to steal a hidden artifact of great power. Time is running out. If the artifact falls into the wrong hands, it could mean the downfall of other preserves, and possibly the world.
It has nearly been an entire year since the events of the first book. At the end of the school year, Kendra sees the new student named 'Casey Hancock' who appears extremely ugly. However, to everyone else, he seems like every girls' dreams. After discussing his appearance with Seth, she realizes that her newfound ability to see magical beings without drinking magical milk has allowed her to see Casey's true form. After he causes many problems throughout the school day, Kendra reckons that he is a goblin masquerading as a student with evil intentions. At the end of a school day a man waiting outside their school tells them that he can get rid of their problem, introducing himself as Errol Fisk. In order to gain their trust, he claims to be sent by Coulter Dixon, a friend of their grandfather's. He tells them that the creature in Kendra's class is a kobold and that they must steal a certain statuette in order to force the kobold to leave. Although Seth is bitten by the statue during the mission, they succeed in procuring it and forcing to kobold to flee. Errol then asks for their assistance in a mission to weaken the Society of the Evening Star. That day after several failed attempts prior, Kendra finally gets in contact with her Grandpa Sorenson, who reveals Errol Fisk's duplicity and sends Vanessa Santoro to bring them to Fablehaven.
The Society of the Evening Star is an ancient organization determined to overthrow magical preserves and use them for their own intents and purposes. The children learn that the society wants to infiltrate Fablehaven to steal a powerful artifact hidden on the property. Adding to the danger, that artifact is one of five keys scattered across the "hidden preserves" that, in conjunction, have the power to open Zzyzx, the demon prison. Grandpa Sorenson, the caretaker, invites three specialists to teach the children, protect the property and search for the artifact: a potion master (Tanu), a magical relics collector (Coulter), and a mystical creature trapper (Vanessa).
The children learn that the statue that bit Seth is Olloch the Glutton, a demon who will continue to relentlessly grow in size and power until it consumes the person who it bit. The Sorensons contact the Sphinx, a mysterious figure who caretakers look to for help and guidance, to try to solve Seth's problem. In that meeting, the Sphinx reveals that Kendra is fairykind, with the power to charge magical objects, and that Seth should remain within the protective gates of Fablehaven until Olloch is destroyed.
Back at Fablehaven, the three specialists teach the children about their various fields. Dale also introduces the children to his brother Warren, who has been in a catatonic state for years. One day, Olloch suddenly appears in the Fablehaven woods, a place he shouldn't have been able to be. Combined with the discovery of a new, unauthorized addition in the registry of people permitted access to Fablehaven, the Sorensons conclude that someone must be a traitor.
That night, Coulter convinces Seth to accompany him to the grove at Four Hills, the place where Warren lost his mind and where Coulter believes the artifact is hidden. Upon entering the grove, Coulter and Seth are instantly paralyzed by immense fear artificially emanating from a revenant. At the last second, Coulter suddenly startles and thrusts something into Seth's mouth. Seth is immediately enveloped in a protective cocoon and the fear vanishes immediately. He waits a day before attempting to break out of the cocoon. Upon escaping, he discovers that the cocoon (with him inside) was consumed and excreted by Olloch, freeing Seth from the curse. Disoriented, he heads towards a beat-up mansion for a better vantage point and sees Warren's cottage.
Meanwhile, Kendra awakes and finds Seth and Coulter missing. Upon discovering Coulter wandering in an albino and catatonic form, they conclude that Seth is dead. Then, Dale is caught in a trap intended to find the traitor. Suddenly, Grandpa Sorenson figures out that Vanessa is the true traitor. As a narcoblix, she can control people in their sleep, explaining Coulter's and Dale's actions and how the traitor gained access to the register. Kendra manages to escape the house unscathed, but everyone else is taken prisoner and imprisoned in the dungeon.
While searching for help, Kendra encounters Mendigo, Muriel's limberjack from Book 1. Captured by the wooden puppet, Kendra convinces a fairy to make Mendigo follow her orders instead. Unable to return to the house because of Vanessa, Kendra orders Mendigo to carry her to Warren's cottage.
At the cottage, Kendra and Seth are reunited and decide to sneak into the house through the brownie entrance using Tanu's shrinking potion. They briefly find their grandparents locked in the dungeon and learn that Vanessa has the preserve key needed to enter the tower with the artifact. The duo manages to steal the key and flee back to Warren's cottage. There, the two argue over the correct course of action. Seth wants to use Tanu's courage potion to defeat the revenant and retrieve the artifact while Kendra wants to flee the preserve and seek help. While Kendra is in the bathroom, Seth takes off with Mendigo to the grove to follow his plan. Seth manages to barely defeat the revenant but is gravely injured and rendered unconscious. All of a sudden, Warren awakes, freed from the curse after Seth's success.
Warren and Kendra enter the inverted tower and attempt to recover the artifact. They proceed through a series of challenges, reaching the final room. They are battling the cat-like boss that gets increasingly powerful every time it is defeated when Vanessa and Errol enter, followed eventually by Tanu and Coulter. During the fight, the sides begrudgingly form a temporary alliance to survive. Errol is killed while Vanessa and Warren nearly die. Luckily, the artifact is a teapot that pours magical healing sand, saving the lives of Vanessa and Warren.
With the crisis averted, they give the artifact to the Sphinx for safekeeping. Additionally, the Sphinx advises that Vanessa be kept in the quiet box in order to prevent her from using her narcoblix powers. The Sphinx leads the previous inhabitant out of the preserve to imprison him elsewhere. More ominously, Vanessa leaves a secret message for Kendra in her cell, in which she accuses the Sphinx of being the leader of the Society of the Evening Star and stating that the Sphinx imprisoned her because he believed she knew his secret.