you are the 9th member of the group and hyunjin is a really big prankster and always targets most of the pranks on you. Some day, he went too far… you were about to get a glass of water but before you could drink it he got the other members to distract you while he swaps out the water with some sort of potion which makes you 5 years younger. You go to your room and looks in the mirror and ur suddenly 16 years old for a week. U look at urself in disbelief