Hirokazu's main goal isn't to tell a tight little story, but rather to peel back the layers of connection between these people and their past. Strikingly serene imagery and the simple plot contrast with flashbacks that give us bits and pieces of the backstory. It's very slow and quiet, yet strong undercurrents of emotion fill the screen. And yes, it also feels long and rather impenetrable! Especially as the plot starts twisting to add mystery and a surprise at the end. But it works wonderfully as a subtle look at people trying to cope with and understand what could make their siblings or spouses join a cult in the first place. Let alone what might drive someone to such pointless brutality.