The book begins where the previous book left off, with the Animorphs having just begun a Z-space transmission with the Andalite fleet. They inform the Andalite fleet of an impending ambush on the Anati homeworld. The Andalites are skeptical of the genuineness of the information thinking that the earth resistance might lie to them in order to become their top priority. They remain skeptical even when Ax confirms the information, saying that he may have confused his loyalties.

Ax, Tobias and Marco intercept a Yeerk transmission that the newly promoted Visser One has a plan to conquer the world by a war between the most populated country (China) and the United States. The humans would exhaust their weapons and would not be able to retaliate. The Animorphs steal an F-16 from an air base and fly out to sea to the USS George Washington. They crash it into the sea so the Yeerks would not think they were being invaded. They infiltrate the ship and find Visser Two, whose host is a high-ranking officer in the Navy (Admiral Carrington). The Yeerks find out that the Animorphs are on the ship and have reinforcement. Bug fighters began invading the aircraft carrier. The Animorphs attack, and fight alongside the non-controller American military personnel. The Yeerks have commandeered an American submarine and plan to use it to launch a nuclear attack against the Chinese and instigate World War Three.

In order to stop this, Ax commandeers an F-14D Tomcat fighter loaded with a nuclear warhead, against Jake's decision, abducts Visser Two and threatens to use the bomb to destroy the Yeerk pool and the city above it (along with the families of all the Animorphs). Visser Two calls off the attack that would have instigated the war. Ax realizes he would have dropped the nuke and wonders if the rest of the Animorphs, particularly Jake, will ever be able to forgive him.

Jake -- Peregrine Falcon, Flea, Seagull, Cockroach, Siberian Tiger

Rachel - Bald Eagle, Flea, Human (female Air National Guard officer Michele Leary), Seagull, Cockroach, Grizzly Bear

Tobias - Human (male United States Navy catapult-and-arresting-gear officer) Flea, Seagull, Cockroach.

Cassie -- Osprey, Flea, Seagull, Cockroach, Wolf

Marco -- Osprey, Silverback Gorilla (Big Jim), Flea, Seagull, Cockroach

Ax - Human (male Air National Guard Captain Joseph Felitti), Human (male United States Naval Officer), Human (male United States Navy Lieutenant), Human (male United States Navy Admiral Carrington), Human (male United States Naval Aviation Fuel Officer)