Alternamorphs #2: The Next Passage is the second and final book of the Alternamorphs series, a spin-off of the Animorphs series. It involves a second-person narrative so as to allow the reader (You) to actually take part in the story. It lies outside of the regular Animorphs continuity. The Next Passage was ghostwritten by Emily Costello.

It's time for our next mission and it's up to you to decide whether you want to join us. You probably already realize that each mission - each battle - could mean infestation, or worse. You probably already realize that we win about as many as we lose. But we are managing to hold the Yeerks back, and one more person could make all the difference.

Just so you know, there are going to be a lot of decisions to make. The right answers keep us alive. The wrong ones -- well that's pretty obvious. So what do you think?

Are you ready to be an Animorph?

This book loosely follows the plots of Animorphs books #20: The Discovery, Megamorphs #2: In the Time of Dinosaurs and #26: The Attack. The book narrates from your point of view, as a sixth Animorph, and you are able to choose your morphs as the story progresses.

The storyline begins by you being new to a school and accidentally finding the blue cube on the way back from a construction site. Marco contacts you, but it's too late, and Visser Three learns about it, attacks you at home, and abducts your parents. However, the Animorphs can save you and offer you to become one of them and fight the yeerks.

After you agree, you'll be given morphing powers, and you'll morph into a horse from Cassie's farm and run around their compound. After you return to the others, you tell them that you are ready for the battle.

But at this moment the Ellimist appears. He is seriously upset and requires you to prove your worth to be another Animorph. This would require an adventure. If you make the right decisions, he will later free your parents, but if you make the wrong decisions, you will be killed. You willingly, and shove on one of two buttons. Button A leads you and the other Animorphs to Iskoort, Button B leads you and the others into the time of the dinosaurs.

If you chose Button A, you are on Iskoort, and the Ellimist offers you three morphs. Hammerhead shark, Andalite and komodo dragon, or Hork-Baijr, red-tailed hawk and fly. The last three morphs are the correct choice.

Shortly thereafter, the Howlers attack, but you can escape for the time being. Shortly thereafter, they find you again, and also attack again. You can escape again, but Cassie is killed by one of the Howlers. Rachel accuses you of being guilty and demands that you promise her to keep you out of the next fight. Giving her the promise is the right choice.

When the Howlers attack again, the other Animorphs fight them while you morphing as a fly. After the Howlers are defeated, the Ellimist says you've proven yourself to him, but makes fun of you in a wicked way. He also says he will only release one of your parents because Cassie was killed by your guilt.

However, you make the right choice and tell the Ellimist to get Cassie back, which he does. This leaves your parents still prisoners of the Yeerks, but you have the chance to free them because you are now a full and accepted member of the Animorphs (though Rachel will probably not like you that much).

Once you've decided on Button B, you travel with the others to the time of the dinosaurs. There you are immediately attacked by a T-Rex, but the Ellimist gives you the choice between two morphs. Wolf or cockroach. Cockroach is the correct choice.

The T-Rex attacks you, but as a cockroach you can escape him and later find out that Ax killed him. Shortly thereafter, a herd of herbivores stomps on you, and you're in danger of being trampled to death. This time, it's the right decision not to morph but just to flee.

Soon after, you will be attacked again by a T-Rex, and you will survive again by morphing into a cockroach. This time it's Jake who kills the T-Rex, and you see a city from a distance (probably a city of the Mercoras). The others let you decide if their go to this city or not, and to visit the city is the right decision.

The Elimist praises you and brings you back to your time, a week before the events. Your parents are free because they never became controllers, and you can choose for yourself whether you want to be an Animorph, or if you prefer a normal life.