It is difficult for Firestar, ThunderClan's leader, to convince ShadowClan and RiverClan to leave. Finally, RiverClan decides to leave when their river becomes poisoned by humans. ShadowClan also agrees to leave when a tree cut down by humans falls in their camp. While trying help ShadowClan, Firestar loses his second life when a tree falls on him. Midnight, an intelligent badger from the previous book, had told the questing cats that a dying warrior will show the Clans the way to their new home. The dying warrior turns out to be the spirit of Mudfur, the former RiverClan medicine cat. Mudfur runs through the night sky as a shooting star and drops behind the mountains, telling the Clans that their new territory will be beyond Highstones. The Clans travel together through the mountains, guided by Brambleclaw, Squirrelpaw, Crowpaw, Tawnypelt, and Stormfur.