Plot of Naruto: The Lost Soldier

In its early stages of the series, the major plot of Naruto: The Lost Soldier has not been delved into yet. The story takes place at the end of Part 1 of the original series, shortly after Sasuke Uchiha leaves the Village Hidden in the Leaves. The story centers around a new protagonist, Mathew Warren, who lives in the United States. Meanwhile, many characters from the original series make appearances as well. The plot is organized into Seasons that each feature their own central plot.

Main Story
Jiraiya calls a meeting with Tsunade, Kakashi Hatake, Asuma Sarutobi, Might Guy, and Kurenai Yuhi. Jiraiya informs them that the terrorist Saisho Teki has targeted an unknown asset to the Village Hidden in the Leaves. Jiraiya states that Saisho getting his hands on the asset would result in catastrophe, and Tsunade sends Kakashi to the United States to retrieve the asset before Saisho can get there. In Roaring Falls, Wisconsin, Matt Warren lives an ordinary life, attending C.S. Parkman Middle School. He has no awareness of the Shinobi World or that anything peculiar happens until he is approached by a stranger, stating that Matt will come with him. Kakashi arrives and intervenes, and identifies the stranger as Saisho. Kakashi escapes with Matt while ANBU Team Ichi fights Saisho, and the two travel to the Village Hidden in the Leaves.

Matt is introduced to Tsunade, who explains to him that he is a Shinobi. She tells him he is descended from a Shinobi who left the Shinobi World. Tsunade and Kakashi tell Matt that he can no longer return home as this would expose him to danger. Matt initially resists but eventually agrees. Matt stays in the Village while Kakashi seeks treatment for his wounds, and the next day, the two begin training. They go to the forest just outside the Village where Kakashi begins teaching him Taijutsu. As Tsunade discusses Matt with Jiraiya and Kakashi's peers, in response to questions about putting Matt on a team, Tsunade states that he is a human and should not be locked away.

Matt quickly masters his Taijutsu training, and later is also able to quickly grasp the use of basic Shinobi weaponry, such as kunai and shuriken. Matt then begins working on Ninjutsu, learning several basic techniques. His Chakra Nature is revealed to be Fire, and he learns several Fire Style Jutsu. He joins Team Kakashi alongside Naruto Uzumaki and Sakura Haruno. As they begin their first mission as a team, they are interrupted to find out that Sasuke Uchiha has been spotted. Team Kakashi's mission is changed, and they travel to the Village Hidden in the Waterfall to locate Sasuke. Upon arrival to the Village, they meet with Shibuki who tells them that Sasuke was spotted near the Great Tree.

Team Kakashi searches, but is unable to find Sasuke, however Shibuki is satisfied that he is no longer a threat to the Waterfall. Team Kakashi then resumes its original mission of gathering participants for the Chunin Exams. After leaving the Hidden Waterfall, they travel to the Village Hidden in the Stone where they meet the Tsuchikage Onoki. They then travel to the Village Hidden in the Grass and the Village Hidden in the Rain before arriving in the Village Hidden in the Sand. There they meet Gaara, and after obtaining the Village's candidates, they move to the Village Hidden in the Mist. After meeting with the Mizukage Mei Terumi, they leave the Village but are then attacked by the Demon Brothers. Team Kakashi manages to defeat the attackers, but Matt is severely wounded and poisoned, forcing them to rush him back to the Hidden Mist for medical treatment.

After Matt recovers, they depart the Hidden Mist and travel to the Village Hidden in the Clouds in the Land of Lightning. They meet with the Raikage A Yotsuki, and after receiving his Village's participants, Team Kakashi returns to the Hidden Leaf. Happy to be home, the four split off to relax and recover, meanwhile Kakashi meets with Tsunade. The two discuss the Exams, Matt's injury, and Sakura's combat development. Later, as Matt is practicing, Kakashi arrives at his house to speak with him. They discuss the Chunin Selection Exams, and Kakashi tells Matt that he is free to choose either to participate or not. Matt decides to, and he, Naruto, and Sakura enter the Exam. They pass the First Exam, and enter the Forest of Death for the Second. In order to pass, they must acquire two types of Scrolls, one from another team, and make it to the tower at the forest's center. They battle and defeat Team Todoki, who possesses the same type of scroll as Team Kakashi, and therefore they are unable to proceed to the tower.

Meanwhile, other teams progress through the Exam as well. Hatsuji Korero battles Rikujo Shinshi. Hastuji easily defeats Rikujo using only E-Rank Jutsu. A day later, Team Kakashi battles Team Masuta. Matt starts to form a friendship with Masuta Tatsumaki, but as the two fight, Matt unintentionally kills Masuta. Severely emotionally traumatized by the event, Matt wishes to leave the Shinobi World, however Naruto and Sakura eventually manage to talk him down. The team proceeds to the tower at the center of the Forest, therefore passing the Exam. They must then participate in a Preliminary to determine who will proceed to the Third Exam. In the first battle, Kinoa Sangetsu defeats Shino Aburame.

In the second match, Matt battles Hinata Hyuga, and despite having an advantage over him, Hinata forfeits the match to save Matt from danger. In the third match, Shikamaru Nara defeats Ino Yamanaka. Meanwhile, in the fourth match, Neji Hyuga wins against Hakuro Tsururi. In the fifth match, Sarura Kuharu kills Natsuhi Kamero, prompting blowback from many spectators. In the sixth match, Kiba Inuzuka and Akamaru battle Rock Lee.