Every year/generation in a certain classroom (same one all the time), there will be a missing desk. One student in the class will have died weeks prior to school starting. A curse will try to 'send the dead back to death' but does not know which student is the dead one. So it kills them one by one, not sparing their families or previous surviors of the curse. The last few episodes become a kill fest.

The curse doesn't control the deaths, the curse just kill people at random but it never kills the dead one, The curse is just there killing students because there is someone dead in the class, even the dead person doesn't know who they are though.

That's pretty much what I said wasn't it? The curse kills people at random until it kills the dead one, not kills everyone but the dead one.

Yeah, I think the characters and reveiwers talked about it like it was sentient enough that I made it sound that way.

is it like Higurashi no naku koro ni?

The storyline isn't multiples like Higurashi nor does everyone try to kill everyone else. It's more or less incidental deaths caused by a curse.

But the curse will kill family members, even if they're not int he town.