Anohana The Flower We Saw That Day : Episode 2

So, are we watching a man who is just imagining hanging out with his dead childhood friend, or an actual ghost that just hasn’t bothered to appear for other people. Honestly could go ether way, seen enough shows were the ghost or second person was just the main character acting odd. Overall, it looks like whatever she is the goal is to get the friend group back together by the end. Why she is just doing this now after many years, idk?