Fireheart's traitorous enemy Tigerclaw has been vanquished and exiled from ThunderClan -- but Fireheart can't shake the feeling that he's lurking out there in the forest, waiting for the chance to strike.
That's not the only problem facing the young ThunderClan deputy in these blazing summer months, as he struggles to handle ominous omens, a disrespectful apprentice with a shocking secret, and a devastated Clan leader who is a shell of her former self.
Meanwhile the forest gets hotter and hotter... and everyone braces for the coming storm....

ShadowClan has a dark new leader, but will he be satisfied with his power now -- or does his desire for revenge burn even more strongly? Fireheart fears that there is a connection between the rise of Tigerstar and the terrible dreams of danger that haunt his nights.
Meanwhile, a mysterious threat has invaded the forest, placing every cat's life in peril. Fireheart's beloved leader has turned her back on their warrior ancestors, and Fireheart can't help but wonder if she's right. Has StarClan abandoned them forever?

ThunderClan's darkest hour is upon them, as Tigerstar's quest for power plunges all the Clans into the most terrible danger any cat has ever faced. In order to save his Clan and his friends, Fireheart must uncover the meaning of an ominous proclamation from StarClan:
"Four will become two. Lion and tiger will meet in battle, and blood will rule the forest."
The time has come for prophecies to unfold, and for heroes to rise...