Chapter 323

That Single Step is the three hundred and twenty-third chapter of Kohei Horikoshi's My Hero Academia.

Summary
Before Class 1-A went to look for Izuku, Tenya asked Principal Nezu how they can provide concrete evidence that the people taking shelter at the school will be safe with Izuku staying too, in addition to the U.A. Barrier. Nezu says that Izuku is the most valuable asset the Heroes have to fight back so having him at an unprepared shelter would be a huge risk. However, he says that U.A. is equipped with the best technology for that reason, even saying it is on par with Tartarus'.

Nezu then tells everyone that after Tomura attacked the school last year, he put considerable thought into how to better prepare, and he ended up adding a few touches to the system of his own design. The reason why Nezu feels so confident that if U.A. was to be attacked and no one would be harmed is because according to him, U.A. can travel! Nezu explains that each section of the school is like a game board, each equipped with mechanisms that will transform it into an underground emergency shelter.