I am number four : the lost files : the search for Sam -- I am number four : the lost files :The last days of Lorien -- I am number four : the lost files : the forgotten ones.

Search for Sam: No one has seen Sam Goode's father, Malcolm, since he mysteriously disappeared years ago. Sam had always fantasized that he was abducted by aliens. But that was before he knew the truth: aliens do exist, and some of them seek to destroy our world. That was before he himself became another one of their captives. Now father and son are both missing. But when a rogue Mogadorian named Adam, who now has Number One's memories, decides the only way to make up for his past atrocities is to return home and infiltrate the Mogadorian stronghold, he'll find the key to saving both Sam and Malcolm's life.

Last days of Lorien. Sandor was tired of being a teenager, tired of going to school and obeying his teachers and playing by his parents' rules. He enjoyed breaking the rules rather than following them. But when he makes one mistake too many, Sandor's life takes an unexpected turn, and he is forced join the Lorien Defense Academy. Sandor had never believed in the crazy idea that Lorien needed to defend itself--Lorien was a peaceful planet, with no apparent enemies. But when Mogadorians suddenly attack, Sandor learns how real that threat was. Now Sandor is one of only a handful of Loric left alive, and the fate of Lorien is in their hands.

Forgotten ones: Adam helped Sam Goode and his father, Malcolm, escape the Mogadorian base in Dulce, New Mexico. Using the Legacy that One bestowed upon him, Adam sacrificed himself and brought the entire facility crumbling down on his head. Miraculously, Adam survives in one piece, and he also discovers something incredible that the Mogadorians had been hiding from the Garde. Separated from his allies, Adam sets out on a quest to find the one thing the Garde have been missing all these years, the very thing that could turn the tide in this war.