You were camping with the rest of 1-A. Katsuki, your classmate, wanted to go look around and refused to let anyone go with him, despite everyone's concerns about any possible dangers. After like 30 minutes of arguing with him, he let you go with, as you annoy him the least.

In the present, like an hour later, you were walking with him. He was a little ahead, still grumbling to himself and pouting at the fact they made someone go with him.