Black Water is the fifth Pendragon book in the Pendragon adventure. The book is set on the territory of Eelong.
Just when fifteen-year-old Bobby Pendragon thinks he understands his purpose as a Traveler -- to protect the territories of Halla from the evil Saint Dane -- he is faced with an impossible choice. The inhabitants of Eelong are in danger of being wiped out by a mysterious plague. The only way Bobby can stop it is to bring the antidote from another territory. Since moving items between territories is forbidden by the Traveler rules, if Bobby chooses to save Eelong he could endanger himself, his friends, and the future of every other being in Halla.
After the travelers lost Veelox's Turning Point, Pendragon came to Eelong to look for Gunny, who had chased Saint Dane to the territory. Bobby was attacked at the flume by the quig-humans on Eelong and was rescued by a jungle cat named Boon. He explains to Pendragon that these cats, called klees, were dominant and intelligent species on Eelong. Humans were known as gars, and were considered less intelligent and generally inferior, to klees. The klees used gars for menial labor, high risk jobs such as foraging and tang-bait, and even kept gars as pets. Boon and other klees initially had difficulty treating Pendragon, whom they saw as gar, with respect.
As Pendragon and Boon made their way to the city of Leeandra, Pendragon witnesses Kasha, one of the klee foragers, rescue a gar on the jungle floor from a tang. Boon told Bobby that she was the daughter of Seegen, the traveler from Eelong.
Inside the city of Leeandra, Pendragon overheard a meeting of the circle of klee, in which the klees debated whether to remove Edict forty six, which would legalize the hunting and killing of gars. The viceroy, Ranjin, was against the repeal, while another member named Timber, who was Saint Dane in disguise, argued strongly for the repeal. Outside the meeting, Saint Dane told Bobby that he was going to Second Earth and Bobby gives chase to the flume.
Back on second earth, Mark and Courtney were placing traveller clothes at the flume as part of their newly acquired acolyte duties when Saint Dane appeared in the flume. The pair witness Saint Dane's hair catch fire and burn his skull. Saint Dane tells them that the rules have changed, suggesting that acolytes can now use the flume. He also gives them a beat up cloth bag for Pendragon, then vanishes back into the flume. Shortly after, Bobby arrived and opened the bag to reveal the severed hand of the traveler from First Earth, Gunny, with his ring still on its finger.
Bobby flumes back to Eelong where he was met by Kasha. Kasha was initially very skeptical of her father's quest to protect Halla from Saint Dane, and refuses to help Pendragon. Back in Leeandra, Seegen's acolyte Yorn tells Pendragon that Seegen help built Leeandra, and Kasha loved him. But once he started talking about the travelers, she lost all respect for him.
Pendragon is forced to join the gars on one of Kasha's forages as tang-bait. He learns that as Leeandra's population of klees and gars grows, they are forced to search for food in increasingly dangerous places. The klees force Pendragon to pick fruit and distract the tang so that the klees could escape safely. On the forage, the team is ambushed by tangs, and Kasha has to rescue Pendragon, allowing a klee to die in the process. As a result, Durgen, Kasha's boss, "confiscates" Pendragon and throws him into a prison to be used by the Handlers.
Mark and Courtney received a message from Yorn, telling them to go to the flume, where they meet Seegen. Seegen reveals that crops in Eelong are being poisoned, and suddenly drops dead in front of Mark and Courtney. Mark realizes that this poison may be the same poison that nearly wiped out all the crops on Cloral, and the pair decide that they must travel to Cloral themselves to investigate. They send Seegen's body back to Eelong, and then flume to Cloral.
Pendragon is stuck in his prison for about 1 month, where he and several other gars are starved and exposed to extreme heat and cold. Initially the other gars fear him because he walks with the authority of a klee, but eventually trust him enough to show him a small amber cube they each carry. Pendragon is shocked to realize that the gars are somewhat intelligent despite being treated like animals, and first hears the name Black Water.
Eventually, Pendragon is pulled out of the prison in order to game-fight another gar to the death for the klees' entertainment. He defeats, but refuses to kill his opponent, causing a fight to break out among the klees. Kasha manages to rescue him and bring him back to her home.
Boon reveals that Seegen has died, and Kasha, Bobby, Yorn, and Boon go to the flume to retrieve the body. Again Bobby tried to convince Kasha she is destined to become the traveler from Eelong and again she refused to accept it. But she did promise to help Bobby find whoever killed her father.
They all go to Seegen's home and Kasha discovers a letter explaining the role of the Travelers to Kasha, even mentioning that a gar named Pendragon would one day show up when Eelong was in trouble. They also find a map leading to the hidden gar city of Black Water, and reveals that he, along with Gunny, have been to see it. Kasha agreed to take Bobby to Black Water.
After Mark and Courtney arrive on Cloral, Spader takes them to Grallion, where Ty Manoo confirms their suspicion that the poison on Eelong was indeed the same one from Cloral. After much debate about the dangers of allowing non-travelers to use the flume, Spader decides that the three of them should deliver canisters of antidote to Eelong.
Pendragon, Kasha, and Yorn follow Seegen's map to Black Water, and find a village full of intelligent, technologically advanced gars. Gunny has been living there and shares that the gars have developed a substance called virloam, which allows plants to grow using nothing but air. They realize that this invention could save Eelong from famine. Gunny also reveals the master plan to free all of the repressed gars and bring them to Black Water in an event called the Advent. He explains that gars all across Eelong are carrying tiny radio receivers, which will allow Black Water to send radio transmissions, giving them instructions and directions to escape to the hidden city all at once.
Yorn then reveals himself to be Saint Dane in disguise. He transforms into a raven and flies off to give the location of Black Water to the klees.
Bobby returned to the flume and found Mark, Courtney, and Spader, who reveal Saint Dane's plot to use the Cloral poison to wipe out Black Water. They decide to split up and send Spader, Mark, and Courtney to Black Water with the antidote, while Pendragon and Kasha would head to Leeandra to convince the Council of Klee to stop their attack. On their way back to the city, Pendragon and Kasha are discovered and arrested by Durgen.
While in prison Kasha and Bobby witness the Advent, and gars all across the city begin to escape to make their way to Black Water. Amidst the commotion, the travelers also manage to escape, heading for the Forager Operation Center. They suspect that the klees will use the flying gigs to get to Black Water and dump the poison, so they begin to sabotage the machines. However, before they can finish, they are ambushed by the klees, and one klee pilot manages to take off with the poison. Pendragon and Kasha give chase in another gig. They manage to destroy the gig by flying above it and dumping tools over the rotor. However, they soon realize that the klees have sent 9 additional gigs carrying poison towards Black Water. Kasha and Pendragon turn back towards Black Water to head them off.
Meanwhile, Spader, Mark, Boon, and Courtney were heading to Black Water via zenzen, when they are ambushed by tangs. During the fight, two of the three antidote tanks are destroyed, with Mark carrying the only remaining tank.
The whole gang is reunited in Black Water, and they plan to hook the antidote up to the city's irrigation system to create a mist-barrier from the poison which covers the entire city. They manage to release the antidote just in time to meet the klees flying overhead.
Saint Dane is present to witness the victory for the travelers, but quickly flies off, telling Pendragon that he is going to Zadaa.
In the aftermath of the Advent, Gunny and Aron, leader of Black Water, pay a visit to Leeandra to negotiate a treaty between the two races and an agreement to share the virloam technology.
Mark and Courtney attempt to flume back to Second Earth, but when they activate the flume, it causes the tunnel to collapse. The collapsing flume kills Kasha and strands Gunny and Spader on Eelong with no way to escape. Mark and Courtney manage to make it back to Second Earth, only to realize that while they spent a month on Eelong, mere minutes had passed on Second Earth.
Pendragon, meanwhile, flumes to Zadaa to follow Saint Dane, where he discovers that Xhaxhu's water supply has completely dried up. He and Loor cremate Kasha, and Pendragon promises to return to Eelong to scatter her ashes.
Black Water was recieved positively by many people. On Amazon, it was rated full 5 stars. On Barnes and Noble, known for sellng the best in children's books, Black Water again rated the full 5 stars. Customer eviews said that the book was " amazing and a non stop thriller..."