Comes full circle!
Sadako, the strange young girl who scared us so much as she crawled out of that TV set in Ringu, is now brought to the forefront and exposed as a flesh and blood shy, cute teenage girl, and not a ghost. This is a prequel to the Ringu franchise. By now, we understand that the "curse" is what "The Ring" centers on and not necessarily the creepy figure with long hair and a white dress.
We understand, as suspected earlier in the franchise, that the VHS tape is a convenient support for a supernatural contagious disease, but it is a complex device, which broadens the enigma. We’re not sure who the enemy is and what exactly we should fear. The cold, dark aura remains, although not as polished photographically as the two previous entries. Some of the camera work isn't up to par.
So, this film is about Sadako before she turned evil. In this plot line, she may be developing powers and appears to be the cause of recent supernatural incidents. Ringu 0 is somewhat similar to Carrie but with a deeper mythology and more style than substance. The script is basically covering basic questions the way a prequel should, but it sometimes indulges in superfluous details.