I have seen the 2 hours special, and frankly speaking, it is
just a summary of what have happen through the 1-37 ep of death
note, mostly highlight, and there are only a couple of scene, which
is not mention in the anime, which is, when Light and the group of
people, are visiting the grave of L, and etc
So what happen to Light, you have to wait till the end of the show,
then you will know or which is my speculation, is that Shinigami
speaking to ryuk, (Light)?