L's successor must ponder L's defeat if he hopes to succeed where his famed predecessor failed. At the headquarters of the SPK, he calls upon the Japanese task force to declare war on Light.

The movie begins with a short narration by the late L who breaks the fourth wall by reviewing what had happened in the previous Relight movie. The very next scene depicts the familiar scene of Near and Mello learning of L's death and Mello proclaiming his emancipation, followed by a scene four years later where Near is just about to leave the Wammy's House. This scene contains a flashback that partially adapted from the special Death Note One-Shot Special manga chapter, where L speaks, without a voice scrambler, to the children of the orphanage before he investigates the Kira case.