We found out who Visser Four is. And he has found the Time Matrix. The machine Elfangor had hidden in the abandoned construction site. The same place we met him on a night none of us will ever forget. Especially me. Now Visser Four has the Matrix, and he plans to use it to become Visser One.
But Jake, Rachel, Cassie, Marco, Ax and I can't let that happen. We can't let him alter time so that the Yeerks will win the invasion. So we're prepared to make the ultimate sacrifice. And, ultimately one of us will lose this fight...
The former Visser Four inadvertently discovers the Time Matrix and uses it to rewrite history to make the Yeerk domination of Earth much easier - America is now a technologically inept, genocidal empire that's ruled by terror and torture. Jake is a neo-Nazi who demands to be called "Supreme Leader" by the other Animorphs, Cassie owns a slave girl, and Rachel is in a re-education camp so that she is "taught her place". None of the Animorphs are aware of the change, as this is, to their minds, what life has always been like (Visser Four having changed events before their births). The Ellimist and Crayak have formed a temporary truce in order to stop Visser Four, and they send Drode to offer the (real) Animorphs a choice: they can refuse the opportunity to track down Visser Four, and the timeline remains as it is; or they can defeat Visser Four and return the timeline to how it originally was - for the price of one of their lives. The Animorphs of course have no choice but to accept, and set out to stop Visser Four's rewrite of time.
The Animorphs pass through many historical events, including the Battle of Agincourt, Washington's crossing of the Delaware (in which, as Marco and Cassie predicted and feared, Jake is killed in the crossfire), the battle of Trafalgar (in which Rachel, Marco, and Ax are also "killed", but not really, due to the only required life -- Jake's -- being taken), and finally Princeton University in the 1930s.
However, Visser Four had made a mistake - although originally planning to kill Albert Einstein at Princeton, his own meddling in the past had changed the future so that Einstein was not at Princeton at this time. Furthermore, Cassie and Tobias make the discovery that Rachel, Marco and Ax have been resurrected, and the remaining five Animorphs realize that the Ellimist's conditions allowed that only one Animorph could be killed - with Jake's death, the rest of the Animorphs are essentially immortal.
Visser Four begins to rapidly leap through time and space in order to shake the Animorphs off, but when he is unable to lose them, he directs the Time Matrix to the Normandy Landing. After navigating through the time-altered battle, which included an Adolf Hitler who is a harmless jeep driver, and the French and Germans on the same side, the Animorphs close in on Visser Four, whose host body - John Berryman - has been fatally injured. Visser Four abandons John's body, and Marco kills the Yeerk by throwing it into a burning tank. Cassie, much to her chagrin, asks John where and when his parents met, and the Animorphs direct the Time Matrix to San Francisco in the 1960s to prevent John's parents from ever having met. With John never being born, he was never infested by Visser Four, who in turn never found the Time Matrix, and the events of this story never actually took place - Jake returns to life, as the Animorphs were never actually at the Delaware crossing. Despite the reset, the group remembers everything, due to Drode having buffered their memories and personalities.
|Morpher||Morphs acquired||Morphs used|
|Jake||War Horse (Unusable, Sario Rip morph)||Peregrine Falcon, War Horse|
|Rachel||--||African Elephant, Bald Eagle, Great Horned Owl, Chimpanzee|
|Cassie||--||Osprey, Bottlenose Dolphin, Polar Bear, Wolf|
|Marco||--||Grizzly Bear (Alternate Universe), Osprey, Silverback Gorilla, Fly|
|Tobias||--||Hork Bajir (Ket Helpak), Human (Main)|
|Ax||--||Northern Harrier, Human (Main)|
- The inside cover quote is "Time and time again..." There is no cover quote.
- ANIBASE: "This is the book that made me swear off time travel (Until the next time.)," K.A. Applegate says. "I was so confused at one point that I didn't know what was going on. But I got to play with some moral dilemmas and I like challenging the readers that way."
- This is the first appearance of Visser Four, who we only last heard about in #18: The Decision, but never actually see at the time.