Rising Storm (Warriors, #4)

Erin Hunter

Fireheart's traitorous enemy Tigerclaw has been vanquished and exiled from Thunder Clan -- but Fireheart can't shake the feeling that he's lurking in the forest, waiting for his chance to strike.
That's not the only problem facing the young warrior in these blazing summer months, as he struggles to handle sinister omens, an 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... Ages 10+.