Opens with Swiftpaw feeling that Bluestar us being unfair in making Cloudtail a warrior, but not him, Brightpaw, or Thornpaw. They know of the strange thing on their territory, and Swiftpaw says that they can take it, asking the other two to go with him. Thornpaw says no and that he shouldn't go, but Swiftpaw insists if they defeat the threat that Bluestar would surely make them warriors. Brightpaw tells Swiftpaw that she'll go with him and off they go!
They find the dogs and are scared (of course), going to run away, but Brightpaw gets tripped by a dog. Swiftpaw whirls, helping Brightpaw get up by distracting the dog, clawing its muzzle. More and more dogs come from the hole in the rock, until there are seven, ready to attack. One of them slashes at Brightpaw's right ear and eye, tearing into them. Swiftpaw cries out in worry for her, snarling and slashing at the dog attacking Brightpaw. Another dog comes in and bites down on his flank, shaking its head before flinging him to the side. Brightpaw groans Swiftpaw's name in concern, leaving Swiftpaw to limp back to his paws, realizing that his left front leg is broken. He manages to leap at the dog nearest Brightpaw, getting knocked to the ground again and feeling his left ear tear and blood pouring out of him. He is near Brightpaw, however, and whispers to her to fake being dead so the dogs go away before passing out from lack of blood.
Later, he wakes up in the medicine den to see Cinderpelt looking down at him. He asks what happened and if Brightpaw is okay. Cinderpelt tells him that she's alive and thanks StarClan that he's okay too. But she also tells him that he'll have to stay in the med-den for a while, as he has really bad wounds. She tells him his left front leg will never heal properly, and that it's a miracle he survived in the first place. Swiftpaw is in great pain, grimacing every second, but he manages to look over at Brightpaw and make a despairing sound as he sees her wounds.
He feels terribly guilty for dragging her into his idea, even though she went willingly. Longtail visits and seeing his former mentor and knowing he'll never be a warrior just puts more guilt on him. He begins to wish he had never even gone to fight the dogs. The next time he falls asleep, he has a nightmare of the Pack coming after him and him not being able to save Brightpaw this time. He wakes up screaming, causing Cinderpelt to come rushing, and he looks around, frantically asking if he saved her. He finds Brightpaw, with Cloudtail sleeping next to her. He is very relieved to see she's okay, but can't help but feel the twinge in his heart at the sight of Cloudtail curling around her and him not being able to.
As the next week goes on, Swiftpaw still can't exactly move from his nest without nearly screaming in pain, but he's trying. Brightpaw has barely been able to for the past couple says. She's still whispering 'Pack, Pack, kill, kill,' in her sleep, but Cloudtail has been helping. Swiftpaw, however, still has nightmares, and refuses visits from his mother and former mentor, not wanting to see them as they would make him feel worse, although there is a part of him that misses them. Cinderpelt has been the only cat that Swiftpaw now talks to. She knows what it's like to have a maimed leg and helps him with it healing and even teaching him how to walk on it, despite the limp.
Finally, when Swiftpaw and Brightpaw are somewhat healed, Bluestar calls a Clan meeting, saying it's time that they received their warrior names. Swiftpaw slumps, hating that it took them nearly dying for her to realize that. He gets his name first: Deathbound, because he should have died when he didn't. He considers it a part of his punishment from StarClan to gain this name, but he is outright horrified upon learning sweet and gentle Brightpaw's name is now Lostface, because of StarClan turning from ThunderClan in their time of need. He doesn't think she deserved that whatsoever, and for once agrees with Cloudtail that he will never call her by that name.
While *shudder* Lostface is healed enough to be in the warriors' den with Cloudtail, Deathbound can never be a warrior, nor is he healed properly. Several weeks go by, and Bluestar has died, leaving the Clan in shambles and sorrowful. Now Deathbound isn't really sure what to do after Firestar gains his nine lives and gives Brightheart her well-deserved name. Firestar offers Deathbound a different name as well, but Deathbound ultimately refuses it. he wants a reminder of what happened so he doesn't make the same mistake again.
Cinderpelt recognizes herself in Deathbound and offers that he become a medicine cat apprentice. He brightens, saying yes and a couple days later, Cinderpelt brings him to the Moonstone, with him meeting Runningnose, Barkface, and Mudfur. Deathbound is nervous about how StarClan is going to treat him, as he still feels terribly guilty about everything. Although Cinderpelt has been a great friend in helping him with everything and has turned into his best friend these past couple months, the scars, both physical and mental, still remain. He still often has nightmares, but they have gotten better.
Upon getting to the Moonstone, Cinderpelt tells StarClan that Deathbound is her new apprentice, and to touch the Moonstone and let StarClan come to him. But when he does, StarClan doesn't come to him, leaving him wandering around in a somewhat dark forest (not the DF, though) where a voice tells him that he needs to let go. The voice knows that Deathbound will never accept himself if he doesn't let go of his guilt and what happened in the past. When he wakes up, Deathbound doesn't quite understand quite understand why StarClan didn't come to him, and he wonders if it was because of what he did and that they don't want him as a medicine cat. He tells Cinderpelt about what happened, and Cinderpelt seems to know what the voice meant, but keeps it to herself, telling him that he has to do it himself. But she also says that she doesn't think StarClan didn't appear because they didn't accept him, but that maybe they were testing him whether or not he was right to be ThunderClan's medicine cat.
When Firestar and Sandstorm leave, and Graystripe fights against the foxes with Blackstar, Deathbound shows his calm expertise with healing his clanmates when they return from the battle. When Firestar and Sandstorm return, and three moons later Sandstorm is kitting, leaving Deathbound alone to deliver her kits as Cinderpelt is elsewhere. The medicine cat is very proud of her apprentice and tells him that it is time he became a full medicine cat. Deathbound looks to her in surprise and smiles, deciding that she is right. Cinderpelt will change his name, though he doesn't know it.
They go to the Moonstone at the next half-moon, and Cinderpelt starts his ceremony, changing his name to Swiftheart because of his courage and loyalty to ThunderClan. Swiftheart accepts his new name with a wavery smile, finally accepting his mistake as nothing more than that, which lead him to become a medicine cat and become best friends with Cinderpelt. He touches his nose to the Moonstone, meeting Bluestar, Patchpelt, and Spottedleaf in StarClan. Bluestar is there to tell him that she shouldn't have named him Deathbound, and touches his head with her nose, calling him Swiftheart for the first time. Patchpelt is there to wish his son a happy life as a medicine cat, and tell him that he is proud of him, something Swiftheart always wanted to hear from his elderly father. Finally, Spottedleaf is there to wish him a long and happy life as a medicine cat, giving her blessing to him.
Swiftheart awakens to find Cinderpelt's blue eyes on him, and she asks without even speaking. Swiftheart nods and tells her they were there, and that they accepted him. Cinderpelt waves her tail in happiness, stepping toward the opening into the cave and calling to Swiftheart that they need to get back to camp and tell the Clan his new name. They do so, with Cinderpelt nodding to Firestar. He leaps onto the Highrock, calling to the Clan to welcome the new medicine cat: Swiftheart. The Clan cheers his new name, but none louder than Brightheart, Goldenflower, and Longtail, despite him being blind and barely standing outside the elder's den. Swiftheart raises his head high, loving his new name. He had done it. He had reached a point that he could be proud that the Clan was proud of him. They accepted him as Swiftheart, and not the cat that had been Swiftpaw, or Deathbound. He was Swiftheart, and he would spend his entire life healing and saving cats.