When he was a kid, Daichi lived on Tanegashima where his father was an astronaut and he met an odd kid to play with. One thing lead to another and through some seemingly unrelated events he had to move away, now an orphan and reserved high school student that life is something he barely remembers. But when a news broadcasts triggers an old memory he heads back he ends up becoming part of an incredible summer to save the world from both aliens and fellow humans and live up to his father's legacy.
I've seen some people refer to this show as being an anniversary project for Bones and, while I can't find any proof of that and the years don't quite match up, it certainly has enough elements from other shows to feel at times like an homage to how Bones makes mecha shows. It would take too long to list off how it relates back to all of the other series, and this really isn't the place either, but it does deal with the themes of friendship and not only finding your group but your place within the group in much the same vein as shows like Eureka 7 did. The characters and the relationships were the heart and draw of the show for me, I do wish somethings had been done differently (such as how quickly Daichi goes from being a reserved, unhappy teen to meeting back up with Teppei and Hana and being a happy, bouncy teen again, especially since the series started exploring it in the final episodes) but by and large I can understand the choices the series made.
I was a bit nervous when I started the show that, since the show was telegraphing so loudly that Hana and Daichi would be a couple, it would focus on the romantic pairings above all and was happy to see that the show focused on the romantic and platonic "pairings" of the characters. We never see much interaction from Hana and Teppei on their own which I did think was odd, and probably says more about their relationship and how aware they were of their own selves than anything else could, but Hana and Akari developed a wonderfully cute friendship and the two of them even referred to Daichi and Teppei as flirting with each other when the two of them would hang out by themselves. The show is a bit uneven developing individual characters however, as I mentioned earlier I felt like they really should have either made Daichi's change a bit more gradual or simply dug into it a bit more, I wouldn't even be thinking about this as much if it wasn't for the "acperience lite" episode in the very final act of the story which reminded me of it. Hana is a similarly odd character, she spends the entire show being a genki, not quite air-headed but innocent character and yet she does become more serious at times. Is it just an act because she likes to be this way or a dissonance of sorts? She reminds me a little bit of Anthy from Revolutionary Girl Utena if she'd been given the power to revolutionize the world halfway through instead of in the final episodes, again it's not necessarily bad but the whole idea still feels rough around the edges. Weirdly enough Teppei and Akari fare much better, especially since Akari never really gets a full character episode to herself. The show does have the characters mention how much happier she is now, much like Daichi, she also has her own off-screen acperience moment, and certainly does prove why she can call herself a magical girl and get away with it but that's it. She's also the most removed from the plot, her actions are important to keep the story moving and she's never reduced to being a tool but she's just not a key player the way the rest of the Midsummer Knight's are, with a bit of re-writing the show could exist without her. Was she only brought along to have someone to pair Teppei up with? Possibly, she's certainly responsible for helping bring him out of his shell and while Daichi might be his best buddy it's with Akari that he has to talk and deal with his problems, out of the cast he has the most interesting development and the biggest arc, even if the show didn't resolve every problem he, like the rest of the cast, is developed enough to be sympathetic and interesting*.
If that paragraph made you go "whoa that's a lot of stuff" then good, the show tries too hard to have a very large cast and fails, I haven't even mentioned yet that it also tries to flesh out the seven planetary gear (the aliens from the summary) figures! This is one area where I think Captain Earth's most compared to Bones predecessor, Star Driver, did succeed better, that show introduced almost all of it's secondary cast within the first few episodes so that whenever they wanted to develop a character they just needed to pick-up the thread and keep moving it along, here the show got too bogged down in it's middle arc introducing all of these characters and instead fell into a rut where half of them never developed beyond that point (Setsuna and Zaku were fine but both of their stories took more than one episode as well). There is one area where Earth did much, much better than SD did or even Aldnoah.Zero from last week, it worked out a way to have the heros face a world-ending threat nearly every week and yet not have them being assured of winning. Sometimes the knights fought the gears on Earth and sometimes they half lost and had to go to space after all, more often than not it would take two of the knights and everyone got very, very thoroughly beat up from these fights. For once the villains were more limited than the heros in how often they could attack and you could feel how the support staff would get nervous when the mechs would be out of commission, knowing that without them the Earth would be, to continue with the fact that the gears want to steal it's libido, fucked.
In the end, I think that Captain Earth's greatest failing was acting as if it was this grand tale that was bigger than just this world and yet it wasn't set-up right to do so. The series villain reveals himself to the Midsummer's Knights literally two episodes before the end, while the viewers have long figured out the series endgame in some ways it still felt too sudden that they would be able to switch gears from fighting the planetary gears to this guy especially since they haven't been privy to the gear's own internal struggles about discovering that they did like some of their lives on Earth. If they had known then focusing on an even more alien evil would have made sense since the gears were already becoming more and more human and therefore less of a threat (also, where in the world DID this villain come from? The series suggests a few things but never concretely enough for me to be sure and this also seems like a rather large detail!). And yet, this show started out rocky but once it hit the halfway point it got better and better and by the end of the show I was enjoying it much much more than I expected (I might watch any mecha series from Bones but I don't expect them to be anything more than okay these days!). The plot worked, the characters were interesting, and if the villains were just too, illogical in their plans at times then, well I will admit that the human villains didn't work so well (even if I understand that the show didn't want them to be defeated too easily, that wouldn't have worked either) and that some of that time had been spent on the gears. The ending was also a bit rushed, like I said, the show tried to cram in so many characters and factions that it lacked the breathing time you really need at the end of the show (and potentially had a huge downer of an ending, for once I'm in the camp that thinks it was the sadder option!). But again, I still plan on buying the show at some point from Sentai and for people who generally like bones and want a colorful, good looking mecha show (I'm hard pressed to think of any moments when the show look seriously off model) then go check this out on crunchyroll or hulu.
*I'm rather curious why the show introduced his "father" early on, mentioned a very interesting possibility related to the planetary gears and being human and then it's never brought up in the show again, this show was a bit too stuffed.