The Andalites have finally arrived, but there's only four of them, and their mision is to assassinate Visser Three - which can only be a good thing, can't it?

But the Animorphs are certain that the Andalites are hiding something, and now it's all up to Ax.

Can he choose between his friends and his people? Can he bring himself to infiltrate the Andalite ship in order to find out the terrifying truth behind their mission? And what of the Andalites' news - the nearest armies are light years from Earth.

Without hope of back-up from Andalite troops, are the Animorphs fighting a losing battle against the Yeerks?