When the Time Comes

When an anxiety-ridden, depressed boy’s sister disappears for four years with no trace, he is unsure what to think. Upon coming back, she reveals that she’s accidentally visited the future, where a person she won’t name is destroying the world. The world ends in a week. Can they stop this person before dimensions collide and the world as they know it ceases to exist? Updates: irregular updates, school is tough; chapters per day may be more than one depending on how bored I am :)