During the flooding of the camp, Hailstar asks for Shellheart's opinion on what to do. He replies that the water is rising fast, and will reach the elder's den soon. At this, Hailstar announces that they must evacuate. A warrior, Brightsky, who is trying to keep the nests together, argues, but when Shellheart states that together they can rebuild anything except for cats who have drowned to save bits of twig, Brightsky reluctantly agrees. Just as they're about to leave, he asks where Rainflower is, and she answers, coming along with Brambleberry. Shellheart narrows his eyes, asking if she was beginning to kit, to which Brambleberry replies that she doesn't know. Rainflower tells him to go help Hailstar, and he turns away, worried for his mate and unborn kits.
Soon, Rainflower begins to kit, and Shellheart carries her up to a wide branch of an old oak tree. There, Rainflower begins to give birth, and Brambleberry asks him if he can go back to get her herbs. He nods, but comes back with nothing, as the water had already flooded the medicine den, destroying Brambleberry's store. The first kit comes out, and Brambleberry hands it to Shellheart cautiously. The second kit is soon born as well, and Rainflower names them Oakkit, after the tree they sheltered in, and Stormkit, after the storm they were born in. They both admire them, and Shellheart states that kits born in a tough storm are destined to be great warriors, and it's a shame they can't both be leaders of RiverClan.
Shellheart is later seen with Ottersplash gathering stems to rebuild the camp. After Stormkit is knocked out of a tree by a magpie, Hailstar tells him that it wouldn't have happened if he had stayed in the clearing. He is amused by this, and calls to Shellheart. Shellheart arrives, and notices that it is about Stormkit. He assumes that his son has done something else troublesome, and asks if everything's okay. Hailstar then tells him that Stormkit will be a brave warrior if he doesn't drown himself before he begins his training. Shellheart suggests they do something about the magpie, as it's becoming very bold. Shellheart asks if they should drive it off or catch it and Hailstar responds by saying that they should kill it, due to lack of fish. Shellheart immediately wants to send out a patrol to catch the magpie, but Hailstar tells him to wait until Rippleclaw's patrol returns.
When Rippleclaw returns with news of ThunderClan taking Sunningrocks, Shellheart growls and climbs the branch to see Pinestar has stretched out on the rocks as if it's his own territory. He then scrambles down and asks if they're going to let ThunderClan stay there. Stormkit says that they could win, but Shellheart snaps his head around and hushes his son. Stormkit once again tries to argue, but Shellheart brushes him off, telling him that he's too young for this debate. Through arguments, Hailstar finally decides that they won't fight. However, he sends Shellheart, Rippleclaw, Ottersplash, and Brightsky to Sunningrocks not to fight, but to warn ThunderClan that Sunningrocks belong to RiverClan. Shellheart digs his claws into the ground, stating that they'll certainly get the message. He and his patrol swim to Sunningrocks, and Shellheart growls that they're on RiverClan's territory. Sunfall, the ThunderClan deputy, steps forward and challenges him to force them to leave. Shellheart calmly replies that it is not a battle worth fighting yet, and conveys the rest of the message to Pinestar and Sunfall. Rippleclaw starts to get aggressive, but Shellheart warns him, and ends by saying they'll take the rocks back when they want them back.
Just before Stormkit and Oakkit sneak out of camp, he and Hailstar are seen beside a tree, heads dipped in conversation. After Stormkit breaks his jaw, he is later let out of the medicine den, and Oakkit says that Shellheart had sat with him night after night. Shellheart pokes his nose into the nursery and asks how he was doing. Stormkit informs him that he had his own nest now, and Rainflower insists on Stormkit sleeping in his own nest, and wants to rename him Crookedkit. Shellheart gets furious at her because of this and calls her heartless. Then, he declares that if she names him Crookedkit, they would no longer be mates and that he would never share a den or a piece of fresh-kill with her ever again. When Stormkit says that he would sleep in his own nest and get his name changed to stop their fighting, Shellheart replies that their fighting was Rainflower's fault, not Stormkit's.
During Oakheart's warrior ceremony, Rainflower tells him that Crookedpaw would never be as great as him. Shellheart gets angry at her and defends Crookedpaw by demanding why she can't keep her thoughts to herself, just once.
Later on, he is selected on a patrol along with Owlfur, Echomist, Timberfur, Softwing, Rippleclaw, Whitefang, Crookedjaw, Oakheart, and Voleclaw to remark the boundaries at Sunningrocks.
When Rainflower dies, Shellheart sees her body and is absolutely devastated by her death. Crookedjaw realizes that although Shellheart never understood how she could be so heartless to Crookedjaw, he never stopped loving her, even when she was cruel to their son. He also notices that his father suddenly looked older in that moment.
After Mudfur announces that he wishes to become a medicine cat, Shellheart tells the Clan that he wants to step down from his position and become an elder. Crookedjaw is named his successor.
Brambleberry tells Crookedjaw that Shellheart is suffering from a painful lump in his belly that has never been survived by any warrior that has had it. Later, Crookedjaw visits him after the Gathering. Shellheart tells his son how proud he is of him, and how proud Rainflower would have been.
Two moons later, Shellheart dies. Crookedjaw is sitting by the river, tells Willowbreeze that he liked to sit there and watch the river, and says that maybe his spirit still came there to fish. When Willowbreeze says he has the warm waters of StarClan, Crookedjaw wonders if he'd miss his old river. Willowbreeze says that she's sure he's watching from StarClan, wanting to see what his sons are up to.
When Crookedjaw is receiving his nine lives, he is the one who gives Crookedjaw his ninth life, along with the gift of loyalty, after which stating that if he'd known about Mapleshade, he would've guided Crookedjaw better during his life.