This is simply not the case. Each generation of Armored Core games have a more or less independent story. There is Definitely some overlap but its not necessary to play all other games (much more that 5 games fyi). No plot summary and you will need to play the game 3 times to get all of the story. Like all fromsoftware games, the story is very fragmented. Im having an absolute blast with AC6. Id say try it out friend.