Two moons after the events of The Darkest Hour, Brightheart has a nightmare of Swiftpaw's death. Cloudtail comforts her and tries to convince her that it can never happen again. She explains that she's currently finding it hard to trust living cats, but she does have faith in their ancestors, StarClan.
When they return to camp, Firestar holds the apprenticeship ceremony for Willowpelt's kits, Rainpaw, Sootpaw, and Sorrelpaw. She hopes to mentor one of them, especially after seeing that Sandstorm is one of the mentors (Whitestorm was the kits' father, and both she and Sandstorm were Whitestorm's apprentices), but she is shocked when Cloudtail is chosen as one of the mentors rather than her. Cloudtail understands she's disappointed and asks her to help with Rainpaw's training. As they patrol the border, they meet up with Longtail and Sootpaw, and Brightheart becomes a bit suspicious of Longtail when he comments that not all ShadowClan cats are bad and she remembers that he was one of Tigerstar's followers. She feels that - whether it has anything to do with Longtail, ShadowClan, or something else - something bad is about to happen.
The following day, they wake up to see two cats arguing about prey missing from the fresh-kill pile. Brightheart feels sick and visits Cinderpelt, who explains that Brightheart is going to have kits. Brightheart tells Cloudtail, who is thrilled, and the news spreads among their Clanmates, who are all happy for them.
A moon later, Brightheart is hunting when she witnesses Longtail and Bramblepaw talking to two ShadowClan cats: Oakfur and Bramblepaw's sister Tawnypaw. Brightheart is still suspicious of Longtail and ShadowClan, and attempts to share her concerns with Firestar, but he just tells her to have faith in her Clanmates, and seems distracted and distant.
Not long afterward, Firestar gives Bramblepaw his warrior name - Brambleclaw - and Brightheart is uneasy about the fact that he shares a suffix with his evil father Tigerclaw. While discussing it with Cloudtail, they realize that the fresh-kill pile seems randomly empty again. Brightheart misses prey due to her now rather large belly, and Cinderpelt suggests that it's time to move into the nursery.
Brightheart still doesn't sleep well, and ends up going out to get a piece of fresh-kill, only to notice that it's all missing. Brightheart accuses Longtail - who's currently on guard - of giving it to ShadowClan. Longtail swears that he didn't, but Brightheart and Cloudtail go to talk to Firestar about it just in case. He reassures them of his faith in Longtail and Brambleclaw.
Brightheart feels restless while stuck in camp and no closer to figuring out what's happening to the prey. Suddenly, a patrol brings Longtail into camp: he was hunting when the rabbit he was trying to catch scratched his eyes, and the Clan fears he'll be permanently blinded. Brightheart thinks how horrible it must be to lose both eyes.
In the following days, she prays to StarClan, worried about him, but also notices that no prey's gone missing from the fresh-kill pile. She goes to visit Longtail in the medicine den, and sees the same despair in him that she felt after her attack by the dogs. She shares tongues with him and tries to reassure him that he can still find a way to contribute to the Clan, even if he is blinded. He promises her that he hasn't been stealing fresh-kill, and she admits that she believes him. Upon returning to the clearing, she goes to the fresh-kill pile and finds that it's all gone, with just some X-shaped gouges in the earth. Dustpelt, who had been on guard, hadn't seen anything, and she and Cloudtail can't detect any scent. Cloudtail reports that Firestar had chosen to go to the Moonstone after the Gathering, and when Firestar finally returns, he immediately goes to speak with Longtail and then heads to his den to sleep.
Brightheart notices more of the strange gouges the following day, and - since Cloudtail is assigned to patrol with him - asks him to show Firestar when they return. But when he returns, Firestar's not with them - they had apparently encountered a kittypet, Firestar told them there was something he had to do, and he left with the kittypet and doesn't return that night. Cloudtail fears that Firestar may have been tempted back to kittypet life after all he's gone through in the forest, but Brightheart still believes in their leader
The next morning, she thinks that maybe the odd markings are caused by a ThunderClan cat with unusually large claws, so she gets the idea to check a couple of her Clanmates' claws by asking them to dig her a burdock root that she supposedly has a craving for. Willowpelt declines, pointing out that she has short claws, and Brightheart wonders if Willowpelt is telling the truth, but when the dawn patrol returns, it's with Willowpelt's body; she was killed by a badger. Brightheart worries about Cloudtail tracking it and wishes she could be there to help, but she knows the best way she can help now is to care for Willowpelt's kits, who have only recently been apprenticed and are now orphaned.
One morning, Firestar calls a Clan meeting and announces to the Clan that StarClan has called him away for a while on a mission, and that Graystripe will be in charge while he's gone. The Clan isn't pleased, and Brightheart fears what will happen with the Clan as tense as it is. To her own surprise, she speaks up for Firestar, expressing that it must be the will of StarClan. Sootpaw calls goodbye to Firestar, and the Clan seems to accept him leaving.
Brightheart has another nightmare about the dog pack, and when she wakes up, she and Cloudtail investigate the missing fresh-kill again, and this time the rest of their Clan seems to notice too. Graystripe scolds the two of them for keeping this to themselves and not trusting their Clan. They apologize, and Brightheart gets the idea to set a trap for the thief: stocking the fresh-kill pile and having the Clan watch it. Nothing happens for most of the night, so they call it quits and Rainpaw goes to get a piece of fresh-kill. Then an owl swoops down into the clearing and snatches up the young apprentice. Brightheart leaps into the air onto its back and fights it until it drops him. The Clan hails her as a hero, and finally, they have some peace.
A few days later, she gives birth to their kit: a little she-kit that Brightheart names Whitekit. She and Cloudtail know that the whole Clan will be there to protect her, and she will one day protect them in turn: the warrior's life isn't easy, but being there for each other is what being a Clan cat is all about.
Tropes appearing in this volume:
- Attack the Tail: Brightheart suggests that they should let their kits hunt Cloudtail's tail for practice. Cloudtail hates getting his tail pulled, but he says he wouldn't mind if it's his own kit pulling it.
- Babies Ever After: The graphic novel ends with Cloudtail and Brightheart curled up together with their newborn kit, Whitekit.
- Birth-Death Juxtaposition: Willowpelt's death interrupts the scene where the pregnant Brightheart first feels her kits move inside her.
- Cabin Fever: Brightheart is frustrated and restless at being cooped up in camp when she's so close to having kits.
- Crying Critters: The ThunderClan cats cry at Willowpelt's vigil.
- A Day in the Limelight: Brightheart's only POV except for a short story in Secrets of the Clans.
- Department of Redundancy Department: Brightheart's repetition is part of what demonstrates how bad of a liar she is: "Being pregnant is making me want to chew on burdock roots. Because I'm pregnant."
- Dream Intro: The graphic novel opens with Brightheart having a nightmare about the dog pack that injured her.
- Due to the Dead: The Clan holds a vigil for Willowpelt's death.
- Ear Notch:
- Brightheart is depicted with some notches in her ears; it's one of the injuries she gained when fighting the dogs.
- Longtail also is shown with the nick in his ear that Firestar gave him, from when they'd fought the day Firepaw joined the Clan.
- Eye Scream: Longtail is blinded when a rabbit claws his eyes.
- Feeling the Baby Kick: There's a heartwarming moment where Cinderpelt explains that the weird thing Brightheart feels is her kits moving, and Brightheart is thrilled and prepares to tell Cloudtail. This sets up a Mood Whiplash when the conversation is interrupted by the shock of a patrol bringing Willowpelt's body into camp.
- Flashback Nightmare:
- The graphic novel opens with Brightheart having a nightmare about when she and Swiftpaw faced the dogs, which had resulted in her injury and Swiftpaw's death. She explains that this is a recurring thing and that no matter what she does in the dream, Swiftpaw always dies. She has the dream again partway through the book.
- Rainpaw admits that he's been having badger nightmares ever since his mother's death.
- Foreshadowing: The shadow of an owl is spotted in the sky when Brightheart visits Longtail. Guess what ends up being the prey thief?
- Humble Hero: After Brightheart saves Rainpaw's life, she doesn't get all the fuss everyone's making over her afterward, calling her a hero; she just thinks that anyone would have done it.
- Insomnia Episode: A recurring problem throughout the book is Brightheart having trouble sleeping due to her Flashback Nightmares and stress about everything going on in ThunderClan at the moment. She spends several scenes looking up at the stars and trying to investigate the prey that's going missing from the camp, and tries to get advice from some of her Clanmates.
- Killed Offscreen: Willowpelt leaves on patrol with some of her Clanmates. They return with her dead body; she was killed by a badger while they were out in the forest.
- Look Both Ways: Sootpaw is nearly flattened by a monster when stepping onto the Thunderpath; he's only saved by Brightheart pulling him backward out of its path.
- Mood Whiplash: The lovely moment of Brightheart feeling her kits move is interrupted by Willowpelt's body being brought into camp.
- Morning Sickness: This is how Brightheart learns she's pregnant; she feels sick while about to eat breakfast, so she visits the medicine den and Cinderpelt tells her she's going to have kits.
- Ominous Owl: The shadow of an owl appears ominously in the sky in some nighttime scenes, and it turns out that the owl is the prey-thief. It attempts to take an apprentice until Brightheart fights it off and it leaves them alone for good.
- Perspective Flip: Some of the scenes in this book were originally from Firestar's point of view in Firestar's Quest, most notably the scene where he and Sandstorm leave on their journey and Brightheart speaks in support of them.
- Pregnancy Makes You Crazy: Discussed:
- Cinderpelt explains that being pregnant can make she-cats excessively worried about the dangers of the forest.
- Brightheart uses this as an excuse to try to get a chance to look at her Clanmates' claws: she claims that being pregnant makes her want to chew on some burdock root, and asks her Clanmates to dig it up for her. Thornclaw seems skeptical at first, but helps out, remarking that mothers-to-be are strange.
- Pregnant Badass: Just days before giving birth, Brightheart attacks an owl to save Rainpaw's life.
- Red Eyes, Take Warning: As if the Red Filter of Doom isn't enough, the dogs in Brightheart's nightmare have bright red eyes, giving us no doubt as to the fact that they're dangerous.
- Red Filter of Doom: Brightheart's Flashback Nightmare that opens the book is depicted in red tones.
- Rouge Angles of Satin:
- Right after Firestar tells Brightheart to have faith in her Clanmates, Graystripe comments about the den on the bottom of the page and there's a random bracket in the text.
- There's a moment where Cloudtail says, "He might want ThunderClan vto accept that Brambleclaw is Tigerstar's son..."
- Cloudtail accidentally refers to the Moonstone as the Moonpool in one scene.
- "The kind of job that will never be finished, no matter hvow hard you work at it."
- A cat makes a suggestion to Brightheart and she replies, "yes, that's an excellent idea, Brambleclaw", but it's clearly Brackenfur she's talking to, considering his yellow tabby coloring.
- Series Continuity Error: Dustpelt is guarding camp when they go to the Gathering right after Longtail's injury. In Firestar's Quest, he had gone to that Gathering, bumping into Firestar as they arrived at Fourtrees.
- Stargazing Scene: Brightheart's dealing with insomnia and nightmares during this graphic novel, so there are several scenes of her staring up at the night sky and praying to StarClan.
- Surprise Multiple Birth: An unusual inversion of the trope; everyone including Brightheart had been expecting her to have multiple kits, but she just had one; Cinderpelt remarks on this fact as Brightheart gives birth.
- Team Title: A Thief in ThunderClan
- Through a Face Full of Fur: Cloudtail's and Brightheart's cheeks blush pink during some of their sweet moments together.
- Wacky Cravings: Brightheart notices the strange claw marks near the missing fresh-kill pile, and tries to discreetly see if any cat's claw marks match those ones by telling them she has a craving for burdock root and asking them to dig for it.
- Wingding Eyes: The dead prey animals have X's for eyes.
