Back in Time, to save our teacher( assassination classroom fanfic)

After 7 years Nagisa is given the opportunity to go back in time and save korosensei. Okuda had come up with a potion to stop Korosensei from blowing up only 7 years late... Itona had come up the machinery to send them back. Class E must chose two people to go back in order to save their beloved sensei.

Disclaimer: Picture isn't mine and neither is assassination classroom:(