Eclipse

Eclipse is a children's fantasy novel by Erin Hunter in the Warriors: Power of Three sequence, the arc that carries the prophecy about three cats of Firestar's line.

The three apprentices have learned what the prophecy says about them, and the responsibility of deciding the Clans' future sits badly with each of them in a different way, because all three want power of their own. ThunderClan is attacked suddenly and every Clan is drawn into a battle of a kind the cats have not seen before. A stranger then arrives to warn them that worse is coming, and for once StarClan does not appear to hold the answers that the living cats need.

The warrior code itself comes under pressure as the Clans work out how much of it they can keep while their territories and their trust in one another are being broken.