okay the goblet of fire is about harry (of course) and there is a triwizard torument......and normaly you have to be a certain age to eneter your name into a goblet, but some how harrys name gets entered and every one wonders why,........well at the end of game when he is playing harry and cedric both go fo the goblet, but it turns out to be a port key...harry and cedric land in a grave yard cedric gets killed and death eater tie harry to voldys parents tomb stone they bring voldy back to life with peter's arm (in book 3 you find out that scabers is really peter).....and harrys blood which now means harry is no longer protected because harrys mom died for him so he was protected by her blood but now that voldy has it, harry can be hurt,......well harry and voldy dule it out in the grave yard........and to make a long story short when harry gets back to hogwarts by useing the port key.....no body belives him about voldy expect ron and hermione. .......
the chareters are: moody, cedric,cho,krum,fluer,hagrid......and most of the old charecters.......there are exchange students in book 4.
and voldy of course is the bad guy.......but there are a LOT MORE detalis I left out, so maybe you should try to read it, it is very good and it is hard to put down.
and one thing that is important is to read the books in order because they all have info leading to the next one, so dont skip from 3-5 or 2-4 because you will miss out on important facts so I recomend that you read the books believe me you wont regret it.