ColdClan: Sky Of Blood 
The mountain lion threat is finally over, with the prophecy kits fulfilling their destinies. However, a closer and possibly more dangerous threat is rising, and both the clans are in trouble unless one of them figures out the mystery first.
Four moons after Skyleap and Sunstorm's visit to StarClan, all is not well in ColdClan. Skyleap's kits are constantly being shunned by their clan-mates for being half-clan, and Sunstorm's terrified that she is not worthy of her medicine cat title when she doesn't treat an injured cat correctly.
HeatClan are also suffering. Foxstar, their leader, is said to have been brutally murdered. The clan of course blame their mountain-cousins, but each ColdClan cat swears they had nothing to do with it. With the new leader, Cloudstar, fearing for his own life, cats in HeatClan get increasingly more frightened and anxious to make an attack.
As the tension grows between the two clans, Sunstorm and Skyleap must help protect the clan they love from the latest threat yet, and discover Foxstar's killer before the mysterious cat strikes again. Is war the only way to finally end the division between HeatClan and ColdClan?