The girls remember that the last time a typhoon appeared in the area, but can’t seem to remember what they were doing apart from the fact that they visited a haunted house. After wishing on the rock to help them remember, the girls find that their past selves from 4 years ago have jumped to the future, and they follow them, intent on finding out what happened as well as making sure they stay safe along the way.
I’m quite impressed at this, actually. Everything turned out to be a time paradox, both for the girls now and the girls back when they were four years younger. I’m not sure whether it was the current-day girls that summoned their past selves into the future, because of course, the younger girls had actually unknowingly made their first wish by wanting to “see what they were like four years ahead” while touching the rock. It was probably the fact they had no idea the rock had magical properties that saved them from freaking out that they had time-jumped, though younger Saki might have had an idea. The typhoon being present wasn’t a coincidence either, as it was needed to make everything seem normal when the older girls disappeared, when it’s actually the younger versions going back in time.
It was hilarious how none of the younger selves noticed who the “ghosts” were (apart from young Saki at the end). Especially standing at the bus station, you have four girls lined up in front of the past selves, with the same hair colour, face and mannerisms. Saki should have been questioning whether she had an unknown older sister instead of thinking that a thief had packed up everything in her house, but kids will be kids I guess. How did a little girl get hold of a nunchuck anyway, when her dad’s a doctor?
In a way, the older girls influenced the younger girls to be who they were – Natsumi’s fear of ghosts came from this incident, and if they hadn’t come to save them from the cliffs, all four would have probably drowned.
Wait, so who saved them in the original timeline? Even if they don’t remember it anymore, hearing the girls sing unconsciously kept their dream of becoming idols somewhere in their hearts, which looks set to become their last activity together this summer before Saki leaves for Tokyo. If it really is their last memory together, then we’d better go out with a bang.