Has everything you'd want in a true crime documentary: a fascinating case, tons of archival footage, linear storytelling, very little (if any) re-enactments, a beautiful score and some stunning photography (Tokyo is a beautiful city). Not to mention interviews with the actual people involved. So many docs these days fail in at least one of these areas so it's nice to see one that does it all right for a change.
Obviously it's a sad case and a terrible situation for her family, so you can't fault her father for wanting answers. And that's another fascinating element to this case is the dynamic between her family (father, generally) and the Japanese police who handle things a bit differently than we're used to in the West.
Overall, one of the best true crime docs I've seen this year. Definitely recommend.