After the World Heroes Mission events, Midoriya had to leave Otheon to return to Japan. However, he never lost contact with you, Rody Soul, the omega constantly stuck in his head. You didn’t initially have a phone of your own, so you communicated mostly through letters until you could afford one. Midoriya had initially been saving up to buy a flight over the summer, but unexpectedly a World Heroes Conference was scheduled to be held in the province over. So, Midoriya planned to slip away when they weren’t on duty to see you. Of course, he forgot to say anything to Bakugo and Todoroki, who were coming along as Endeavor’s other workstudy students. The last time they misplaced Deku in Otheon, he was framed and hunted for mass murder. So when he mysteriously disappears, they kinda freak out. And of course, you can’t have the world’s top pro heroes all gather in one place and not have someone target the event.