“That means I’ve gotta kill Higuchi without letting go of this notebook. If I manage to do that, ownership will transfer back to me and my memories won’t disappear.”
Higuchi is arrested on suspicion of being Kira and causing multiple murders to occur throughout the world. As Soichiro and Mogi apprehend him, L instructs them to place a helmet on his head through which they can communicate with a microphone. Asked by L how he kills, Higuchi admits that he has "a magic notebook that kills people", knowing it sounds crazy. Soichiro finds the Death Note in the car, and while holding it, ends up seeing Rem, to his horror and Rem's blatant staring; Mogi follows suit. L eventually gets his hands on the notebook himself and realizes that Shinigami do exist. He also silently remembers every mention of a notebook during his investigation, including the fact that the second Kira met with the first Kira on May 22nd by stating she wished to exchange notebooks in Aoyama, the same day Misa met Light for the first time; L then realizes that there is another notebook in the human world. While he thinks this, Light takes the Death Note from L's hands, causing all of Light's memories of being the original Kira to return. It is revealed that Light had planned the entire thing: the notebook Higuchi used was Light's original Death Note, with Light having made it so that Rem owned that Death Note and he forfeited Misa's while in confinement, thereby allowing him to gain all of his original memories. Also, when he gave away his Death Note, he had Ryuk add two fake rules that have no effect, one stating that after having written in the book, its owner must continue to use it at least once every 13 days or perish, the second stating that if the book is made unusable by burning or shredding, everyone who has touched the book will die. Light then enacts Higuchi's death in front of L by writing his name on a scrap of the Death Note hidden in his watch; though outwardly he displays dismay as to the inability to interrogate Higuchi, internally he is plotting L's death next.
The investigation team reviews the rules written in the book and find out that they can do little to get rid of it based on the first fake rule. Light silently thinks that this is what he planned, as if they tried doing anything with it, they could lose everything, unaware that they will mean his downfall. On top of this, they are facing another dilemma: the second rule "proves" Light's and Misa's innocence. The very specifics of the rule draw L's suspicions. He asks Rem if all Death Notes are the same, and if there are more in the human world. Rem says that there MIGHT be more and that they are the same, not entirely lying but also keeping Misa safe. The other members decide to let Light and Misa go, much to L's silent dismay. Light, however, decides to continue investigating regardless, albeit without the handcuffs.
After the Task Force says goodbye to Misa, Light orders Misa to recover the other Death Note he had hidden and buried at a particular site a few months earlier. Misa goes to the site and regains her memories, while also finding a slip to write down the true name of "Hideki Ryuga," only for her to have forgotten (later revealed to have also been planned). Returning from the Shinigami Realm, Ryuk greets Misa, who makes a second deal for the Shinigami Eyes in order to find out L's true identity (and also trading a human apple for a Shinigami one, which Misa finds sandy). Misa and Ryuk then return to the headquarters and reunite with Light out front, where Rem notices via a security camera that Misa has again halved her life, and now has less than a month to live. Light then has Misa be his companion for the New World. Watching over it all, L silently realizes he is going to die and begins to make the final master plan of his short life.
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