Even though you like the series of Death Note, I didn't see the point that you just watch this as well. A whole story was completely different from the story of Death Note. Only a few connections.
The plot is when L waited to die because of Death Note, he'd received a gift from F who died due to infection. That virus was made by a scientist and plans to spread it all over the world to decrease human population.
To stop that plan, L started to work on it with the gift and a girl who is a daughter of the scientist who was killed by that virus.
Could L find a solution to stop this plan before he died?
Could L stop the people who want to change the world?