Welp MC, looks like your wish of getting involved on a mystery and chasing after the culprit and corners him with intellectual deductions is about to be realized. Careful of what you wish for i suppose.
@nachtness, wait, you really see the MC as retarded? I mean, yes he's dense but he actually cherish his childhood friend's birthday, it's even revealed that if he knows that she still remember the marriage promise, he's going to go through with it. Not to mention his wit about dangers and how fast he understand the supernatural nature of the whole incident thing. His denseness is actually on a pretty realistic scale for a highschooler. He's more carefree than retarded, unless you saw no difference between the two.