Ryuk, who can see the lifespan of humans, reveals to Light that Misa Amane, a popular idol who Light is a fan of, may only have a few days to live. Light attempts to warn Misa after one of her concerts but fails. However one of her security guards, Tsutomu Yukida, overhears Light’s warnings and offers to help Light protect Misa. Meanwhile, L meets with a few members of the Japanese police, one of which includes Soichiro, in order to form a task force dedicated to capturing Kira.

With “Raye Penber” still following him, Light realizes that L’s phone call was, in fact, a trap. Light becomes determined to kill all the FBI agents involved in the Kira case in order to disperse suspicion on him. In the midst of his planning, Light remembers finding a picture of Cathy Campbell, the name of Raye’s lover, during the bus-jacking incident. Meanwhile, Misa sacrifices half of her remaining lifespan to Rem in order to receive the shinigami eyes, allowing her to see the real names and lifespans of anyone she looks at.

Suspecting that Mark Dwellton met with Kira before his death, L plants cameras and listening devices in the houses of families Mark was following. Light quickly realizes this and formulates a plan to temporarily prove his innocence to the task force members. However, L’s suspicions do not waver and he enrolls into Light’s university in order to investigate him personally.

Misa reveals that she has fallen in love with Light and wishes to help him kill L. At the same time, L reveals to the task force that, based on the killings made at the wake of the recent broadcast, a second Kira may have appeared. L then suggests recruiting Light into the investigation team both as a way to move the investigation further and get him to possibly reveal himself as Kira.

Light approaches L and the task force and requests to be placed under surveillance on the grounds that he could subconsciously be acting as Kira. After Light is incarcerated, the killing of criminals stops for some time, but they resume once Rem passes the notebook to a new owner.

Light and Misa join forces with the task force in order to capture Kira. However, L’s suspicions of the two do not waver as he suspects that they intentionally lost their memories by passing their powers to someone else. After realizing that they are under suspicion by the authorities, a group of Yotsuba executives enlists the aid of the investigator Babel, who is revealed to be Near in disguise.

After the notebook is confiscated by the task force, a fake usage rule written by Ryuk convinces L that Light and Misa are innocent. Near is revealed to Soichiro to be L's successor whilst L makes plans for a final confrontation with Kira...

L reveals that he had tricked Light into writing into a fake notebook, thus exposing the latter as Kira. After Light confesses to L, the rest of the task force enter the warehouse only to see L die from a heart attack, courtesy of Mikami. Since only L heard the confession, Light convinces the task force members that L gave Light his real name and wrote it down in an act of self-defense. After L’s funeral, Near takes over L’s duties as head of the task force and focuses the investigation on the prosecutors that came into the task force headquarters the day L died.

In order to save Sayu, Soichiro and Light take the Death Note to the place indicated by Himura. Additionally, on the instruction of Near, Mogi and the rest of the police prepare to storm the place.

Soichiro has followed in the footsteps of L in risking his life to stop Kira/Light. Light, who has made the decision to do whatever it takes to create his ideal, crime-free world, decides to mobilize the police force to get rid of Mello. But Mello has also erected a scrupulous set of traps, and intends to risk everything to prove that Light is Kira!