When she was younger, Makoto had asked Azusa about the iDOLs having hearts because Mami and Ami had believed so. Although Azusa agreed that it’s a strange concept, she explained that riding in an iDOL sometimes makes you want to do your best with it or treasure it. It might have been difficult for Makoto to understand, Azusa felt that Makoto would experience it someday when she gets to pilot the Nebula. Back in the present, the girls are going through the harmonizing process, including Iori for the Nebula. When the results come out, Joseph finds that the Imber and Haruka did as well as expected, but the problem is with the Nebula – the graphs show Iori with a larger growth rate than Makoto. After getting Ami’s opinion, Azusa announces to the girls that Iori is now the master of the Nebula with Makoto as backup. Makoto is shocked to hear this, but Iori is of course elated. Tracking down Ami in the hanger, Makoto coldly asks why she came back. Ami replies that when she heard the Imber’s melody for the first time, she felt something that she had never felt before. Makoto tries to tell her that iDOLs are just machines and what’s needed is the right technology and good judgment. That’s the way Makoto has done it up until now, but Ami points out that this way won’t let Makoto grow any further, and the Nebula knows this. Ami thinks that Makoto understands this too, but she just doesn’t want to admit it. This gets Makoto so angry that she grabs Ami’s arm, but Makoto is also conflicted between the thought of iDOLs having hearts and her memories of a bloody event that happened many years ago inside the Nebula cockpit. Realizing that she’s hurting Ami’s arm, Makoto lets go and still refuses to accept it.
Iori learns a little later that she’s going to be sent on a recovery mission with the Nebula for a fragment of the moon. Unbeknownst to her though, Makoto logs into her computer with Azusa’s password in the middle of the night. When Iori takes off in the Nebula to start the mission, Makoto thinks privately to herself that she wants Iori to show her proof that iDOLs have hearts. The mission proceeds relatively smoothly at first, and Iori is able to grab the moon fragment with the Nebula. The problems come when the Nebula’s return approach towards the planet gets screwed up, and it runs the danger of crashing onto the surface. These problems get compounded when Mondenkind NA shoots three missiles at the Nebula and the moon fragment. Unable to get out of the way, the Nebula gets caught in a huge explosion in space. In the aftermath, the heavily damaged Nebula is brought back to base, and Iori is fortunately okay. However, even though both Haruka and Ritsuko think that it isn’t possible, the data of the accident points to the cause being a calculation mistake on Iori’s part, and she is thus removed from being the Nebula’s Idolmaster. Makoto meanwhile takes a shower at home where she tells herself that this is proof that iDOLs don’t have hearts, but she then repeatedly curses as she starts crying. Once out of the shower, Makoto notices that Azusa is home, and Azusa offers to tell Makoto her new system password, but Makoto feels that she doesn’t need it.
The next day, Makoto and Haruka are told about the fourth iDOL being found in Iceland and how the Turiavita are already after it. Thus, the two girls and their iDOLs are being sent out.
I thought there was a decent chance they’d kill off Iori thanks to Makoto’s sabotage because the show could use a jolt to get it really going, but she manages to survive the missile blast. Still, even without Iori dying, things just got a lot more complicated and a lot more interesting with Makoto and her past. I assume that Makoto won’t just get away with what she did, so there’s likely going to be a confrontation sometime in the future if or when this all comes to light. The fact that they give Makoto redeeming features like her weakness for the crab makes me think that she’ll still remain a good guy, but she’ll have some personal demons to confront and exorcise. She seems particularly traumatized by that past event where it looks like Azusa got badly injured in the cockpit of the Nebula.
As for the rest of the story, the preview suggests that at long last, the bad guys are actually going to do something again, and we might learn more about Chihaya.