1.open ninja saga
2.open cheat engine 5.6.1
3.play ninja saga
4.in cheat engine,change the value type from <4bytes> to <text>
5.then,scan <premium>
6.select all address and change the value to <free user>
7.go to mission room
8.now you can do all the PREMIUM mission NOW
9.ENJOY THE HACK =)