As Leafbare approaches, a new danger threatens the Clans. Twoleg construction has encroached on Clan territory, poisoning the stream and making prey especially scarce for SkyClan. Meanwhile, their leader, Leafstar, is struggling with a loss of vision while trying to maintain authority over a Clan that increasingly doubts her ability to lead. In ShadowClan, Tawnypelt senses peril as the Twoleg construction threatens the Moonpool, but she can't get anycat, especially her son, TigerStar, to listen. Frustrated with the younger cats who don't respect her, she decides to take matters into her own paws. In the midst of the chaos, Moonpaw, an apprentice struggling to understand the mysterious voice in her head, thinks that she might be having visions. But the voice becomes increasingly sinister, and Moonpaw wonders if it's a sign of darkness on the horizon.

Erin Hunter’s #1 bestselling Warriors series continues with the second book in the Changing Skies arc, as the Clans continue to navigate an ominous prophecy that foreshadows the end of the cats' connection to StarClan. Still healing from an accident that almost killed her, Tawnypelt is eager to share the message she received from StarClan about a “great peril” looming over the clans. But her vision is dismissed by her son and leader, Tigerstar, leaving Tawnypelt with no choice but to take action on her own. Racked with guilt that he caused his father’s death, Starlingpaw is determined to atone for his mistake. His chance comes when Tawnypelt warns him of a “two-faced cat” intent on destroying the clans. Believing himself uniquely suited to find this cat and stop them, Starlingpaw seizes on the opportunity to prove that he is an asset, and not a liability, to SkyClan. Moonpaw is settling into her role as a Thunderclan apprentice, even as she continues to grapple with the voice in her head. But the more she tries to ignore the voice, the louder—and angrier—it grows. Meanwhile, Twolegs have set their sights on the Moonpool, preventing the Clans from reaching StarClan. Will the cats find a way to reach their ancestors before all is lost?