what movie is this?,please help!

So i vaguely remember this movie but it starts something like this so there is like this girl who i think in halloween(might have been her birthday) went to this other world in a school bus,her mother was someone powerful from that place (not sure) and then all i remember are two more things 1)there was a show(not sure what it was might be a show,but basically something inside a hall kinda place),2)there was this red locket(necklace)thingy inside a book and the girl took it and destroyed it or threw it away,not sure about the take and destroy part but i am sure that there was a necklace with a red stone hanging to it,or it might have been just a red stone.please if anyone can tell me anything about this i will be very thankful.