The GRUDGE 3 is to THE GRUDGE what POLTERGEIST 3 is to the first POLTERGEIST movie. In fact, it also takes place in Chicago and one of the main characters is a little girl who can see the ghosts.
A young Japanese woman in Tokyo reads about the mysterious deaths that have happened in a Chicago apartment building and believes that the evil has now located there. It turns out that she is the sister of the murdered woman, Kayako, and believes she can stop her. There's this cockamamie flashback of when she talks about how their mother exorcised evil spirits and transferred them into the young Kayako--and because of this, presumably, she is paying price.
People living in the building, such as an artist (Marina Sirtis) and the landlord are killed by the vengeful ghosts. The main crux of the story is about a young guy who is the super of the place and lives there with his two sisters. One of them is soon moving away with her boyfriend and the other sister is young and suffers from bad asthma. Towards the end, when the brother gets violent and starts acting crazy, the movie seems like it's turning into AMITYVILLE 2: THE POSSESSION.
This is, by far, the worst of the series. Enough, I say. Enough!