Tides of the Dark Crystal is the third of The Dark Crystal young adult novels released on December 24, 2018.
Amri, Naia, Kylan and Tavra reach a ship that is captained by Onica, a member of the Sifa Clan and Tavra's girlfriend. She brings them into a Far-Dream, where they see All-Maudra Mayrin argue with her daughters Seladon and Brea as she prepares for the arrival of SkekZok the Ritual Master and SkekUng. They also see a Skeksis carriage on a nearby road and Naia rushes towards it with Amri and Tavra in pursuit. They rescue Rian, but SkekSil the Chamberlain drinks Mira's essence to destroy the proof that the Skeksis are draining Gelfling.
Once they escape from SkekSil, they end up in the Dream Space, where Aughra tells them that they must light the fires of resistance. She communicates with Mayrin, who is convinced of the Skeksis' guilt. Once they leave the Dream Space, Rian sets off on his own path while the others make for Cera Na.
At Cera Na, the group attempts to convince Maudra Ethri to rise against the Skeksis, but she refuses. They find Tae, a childhood friend of Ethri and Onica, who appears to have been drained. Ethri comes to investigate and is joined by SkekSa the Mariner, whom the Sifa view as a benevolent figure. She explains that Tae has been poisoned and invites them onto her ship, which is a tortle, so that they may heal Tae. As he and Naia assist SkekSa in the healing process, Amri attempts to kill SkekSa, but Tavra takes control of him and stops him. SkekSa notices Tavra and becomes suspicious, believing an Arathim to have taken over Amri. Amri insists that this is not the case and SkekSa vows to find out what has really happened. Once Tae is healed, the Gelfling leave the ship.
The next morning, the Sifa begin to sail out into the Silver Sea. The company catch up to them and convince them to light the fires of resistance and join their fellow Gelfling in the fight against the Skeksis. In the ensuing celebration, Tavra is taken by a thief and the others chase after him. Once they catch him, he identifies himself as Periss, a member of the Dousan Clan. He returns Tavra to them and promises to use his Crystal Skimmer to get them out to the Crystal Desert and meet with the Dousan in exchange for Naia's dagger and Amri's firca.
The group flies over the Crystal Sea when a storm gathers and they are attacked by several Crystal Skimmers who are infected by the Darkening. One of them grabs Onica in its mouth and Amri allows Tavra to control him, at which point he flies out and saves her. They are found by Periss' older brother, Sandmaster Erimon, who takes them to the Wellspring. Once there, he orders Periss to return Naia's dagger and Kylan's firca.
The storm later enters the Wellspring and begins to destroy everything in its path. The group work together and unite the Dousan, and with their combined efforts they revive the Oszah-Staba, which drives the storm away. The Dousan light the fires of resistance, but the celebration is short-lived as Sandmaster Rek'yr arrives and informs them that Maudra Seethi has been called to Ha'rar and All-Maudra Mayrin is dead.
Periss flies the group to Ha'rar and before he leaves he gives them Sifa pretties to atone for the valuables that he took from them. They sneak into the city and narrowly avoid being caught by SkekZok and SkekUng, whom they overhear admitting that they killed Mayrin. They find Tae, who takes them to Onica's nearby ship so that they can make a plan. That night, Amri is visited by UrSan the Swimmer, who tells him that ice is the key to calling the Vapra Clan to their cause.
The group disguise themselves in Vapra garments and climb into the icy mountains above Ha'rar, where they find UrSan's dwelling. They are found by SkekSa, who came seeking her UrRu counterpart. She offers to let the others escape if Naia will surrender herself to her, but Naia refuses and SkekSa attacks. As Naia and Tae hold her off, Amri and Kylan help Tavra pass on a message to the rest of the Vapra which inspires them to lift the fires of resistance. As the fight continues, Tae cuts off one of SkekSa' hands and the enraged Mariner attacks her with a thunder egg. Tavra takes control of Tae's body and she and Naia glide Kylan and Amri to safety on Onica's ship.
Naia heals Tae's wounds, but states that she will not wake any time soon, if at all. SkekSa's tortle then swallows their ship and they are captured. Once Amri awakes, Tavra (who has once again taken control of Tae's body) informs him that Naia managed to escape. SkekSa then enters and orders them to move, as she has plans for them. Despite the drastic situation they are in, Amri is hopeful, as they are united as Gelfling.