Applegate Katherine Alice. The Animorphs 18. The Decision

The Animorphs discover that a high-ranking member of the Secret Service, Hewlett Aldershot III, has been intentionally injured by the Yeerks and is being kept secretly in a hospital where he is heavily guarded. Since he cannot be infested while in a coma, Visser Three acquires his DNA in hopes of impersonating him to eventually acquire an even more senior official. They decide to morph mosquitoes with the theory that they can acquire him by sucking his blood without being in their natural forms where the Yeerk guards might notice them.While in mosquito morph, they are transported to Z-Space when their extra mass is caught in the slipstream of an Andalite ship heading for the Leera where there is a Yeerk invasion underway. Just before they suffocate, they are rescued and taken aboard. Once on the ship, Ax begins to ignore the Animorphs, instead following orders from the captain. The humans are told to stay calmly in a room while the Andalites do all the work. Unfortunately, the captain of the ship reveals himself to be a traitor. He incapacitates the other Andalites on the bridge, stunning most and amputating the tail blade of the tactical officer. Ax is held, unharmed, as a hostage. Ax calls out to the Animorphs for help but they reveal to Ax that they are already present in the room. Cassie and Ax distract the captain long enough for the tactical officer to kill him. As the ship is about to be taken by the Yeerks, the tactical officer instructs them to leave while he initiates the self-destruct sequence.Animorphs is an English language science fiction series of young adult books written by K. A. Applegate and published by Scholastic. It is told in first person, with all 6 main characters taking turns narrating the books through their own perspectives. Horror, war, dehumanization, sanity, morality, innocence, leadership, freedom, and growing up are the core motifs of the series.The story revolves around five humans, Jake, Marco, Cassie, Rachel, and Tobias, and one alien, Aximili-Esgarrouth-Isthill (nicknamed Ax), who obtain the ability to morph into any animal they touch. Naming themselves "Animorphs" (a portmanteau of "animal morphers") they use their ability to battle a secret alien infiltration of Earth by a race called the Yeerks. The Yeerks are a parasitic race of aliens resembling large slugs that take humans as a host by entering and merging with their brain through the ear canal. The Animorphs fight as a guerilla force against the Yeerks, led by Visser Three, and their program to take over the human race. Morphing into animals allows them to battle the various armies of aliens that the Yeerks use, but it also protects their identities. As far as the Yeerks know, only Andalites like Ax have the ability to morph, and if they knew that the Animorphs were mostly human they would be able to easily find out who they are. Protecting their identities becomes more and more difficult as the series goes on because though someone with the ability to morph can change into any animal that they touch, they can only stay in a morph for two hours or they will permanently become that animal. Throughout the series, we see how the war affects the characters in different ways, mentally and physically.