The Fourth Apprentice

The Fourth Apprentice takes place approximately six moons (months) after the end of Sunrise during greenleaf (summer). The book opens at the monthly full moon Gathering. The four warrior Clans are suffering due to a drought, which has been especially hard on RiverClan, whose main prey are fish. Leopardstar, leader of RiverClan, accuses the other Clans of stealing fish from the shrinking lake. She claims that RiverClan has whole ownership to the lake, and therefore, all that was in it, as her Clans' territory. The other Clans are outraged by this plan, but Firestar allows them to patrol in order to prevent a battle.
Dovekit and Ivykit afterward become apprentices with Lionblaze as Dovepaw's mentor and Cinderheart as Ivypaw's. Dovepaw expresses some of her powers by noting how she sees and hears cats from all the way across the lake. Later, Dovepaw speaks of seeing brown animals up the river building a dam out when she was in the forest, but no other cat believes her. Lionblaze speaks to her, and realizing that she is the third cat of the prophecy, although Dovepaw does not take this fact well. Dovepaw's is revealed to be one of the Three and her special power is to see and hear things very far away, like clairvoyance. Dovepaw and Lionblaze tell Firestar that Dovepaw receives a dream from StarClan the animals called beavers are building a dam upstream that blocks the river. Dovepaw receives a dream from Yellowfang, ThunderClan’s old medicine cat, and is told a prophecy: After the sharp-eyed jay and the roaring lion, peace will come on dove's gentle wing.
Lionblaze creates a plan to travel up the stream and find a way to unclog it and bring the water back, a journey that would include a patrol from each Clan, and Firestar agrees. All four Clans end up joining the journey, each sending two cats. Lionblaze and Dovepaw are chosen for the trip, and meet up with Toadfoot and Tigerheart of ShadowClan, Whitetail and Sedgewhisker of WindClan, and Rippletail and Petalfur of RiverClan. Ivypaw is immediately jealous and unhappy of that her sister is chosen to go on the journey, and becomes cranky back at the camp. The chosen cats set off on the journey, traveling up the quiet stream-bed until when they encounter a pen of rabbits that are owned by Twolegs, but before they can eat them, three kittypets named Seville, Jigsaw, and Snowdrop confront them. They leave the rabbits eventually, and soon travel up to the beaver's dam. The cats, after first finding the dam, meet a loner named Woody, who seems to refuse to help them, though later on gives in. They plan an attack on the beavers, but the beavers prove too strong, badly wounding the cats and killing Rippletail.
Meanwhile, back in ThunderClan, Poppyfrost, heavy with Berrynose's kits, becomes worried that Berrynose does not love her, as he forces her to stay in the nursery, and disappears. Jayfeather follows her to the Moonpool, spotting Breezepelt following her too. Jayfeather attempts to comfort Poppyfrost, but is interrupted when Breezepelt shows himself again, attacking Jayfeather. Breezepelt declares that he will not stop and that the rule of killing a medicine cat no longer affects him. Another cat, unknown to Jayfeather (Brokenstar), aids Breezepelt in the attack, but Honeyfern comes to Jayfeather's rescue and chases them off. She tells Jayfeather that she is proud of Poppyfrost and Berrynose, and that Berrynose truly does love Poppyfrost, and he is only terrified of losing her. Yellowfang then appears and Jayfeather is told that the power of the Dark Forest is rising, and that there will be a war between StarClan and the Dark Forest. StarClan needs a power greater than they are: the three prophecy cats.
At the dam, the patrol creates a plan try and get rid of the dam. However the plan needs more cats so Lionblaze and Dovepaw set out to find Seville, Jigsaw, and Snowdrop, the kittypets they met earlier. The kittypets agree and with their help, the dam is successfully unclogged and the Clan cats return to their Clans. Poppyfrost gives birth to her kits, and Jayfeather sees Tigerstar, Hawkfrost and Brokenstar watching over them as if they want to take the kits away.
At the conclusion of the novel, Jayfeather tells Lionblaze about Breezepelt's attack towards him, and Lionblaze is shocked. Jayfeather also tells him about the tom that aided Breezepelt, and Lionblaze confesses meeting Tigerstar in his dreams in the past. They realize that Breezepelt must have been recruited by Tigerstar to help fight in the war between StarClan and the Dark Forest. Tigerheart, Lionblaze says, was also seen using a move Tigerstar had taught to him in his nightly visits, and so is also believed to be being trained.