There's not much in the way of a story line. But it makes up for it with the gameplay. There's ALWAYS something to do, and guaranteed to provide hours of entertainment! My personal favorite little bonus is the AB quizzes you can participate in for in game currency (sweatcoins). I absolutely recommend.

Go to settings, have a VPN (Spider OVPN) and change your App store’s region to Japan (Settings —> Media and Purchase—>View Account —>Change country/region. You can also skip the Billing and stuff as it isn’t important(unless you actually live in Japan)) After that, you make a new Apple ID account. Then you can install JJK phantom parade(use the App Store) and play!(Use a VPN too) Have fun playing!