I suppose I should remind readers up front that I'm not a huge manga fan. Reading backwards isn't my choice, but I can do that if the story is worth it. the problem is that the stories all-too-often aren't worth the effort of reading unnaturally. This was one such.
The premise was amusing and entertaining enough, but in the end it's the story. I can read a story which has no plot if the author writes well enough. I can't read the perfect plot if the story is written badly, uninventively, or boringly. The premise here is that a young girl is chosen in school by a classmate for testing for what seems to be UPS in space, although it's also space police - or maybe something else? I dunno and that's part of the problem. The scope of their 'duties' is so vague as to be limitless.
What were these people supposed to be doing and why are girls taken out of school to do it? No explanation. Their travel results in time-dilation, so their return is only a minute or two after they left, but they have subjectively experienced the entire time - even if it's many hours - that they spent doing this job, which consists of flying spacecraft. These craft are designed to look like swans for reasons which are unexplained - assuming they even exist.
The girls come back already exhausted and still have the rest of their own school day to finish. It's beyond credibility that something wouldn't go wrong, and it's hardly surprising that this girl who recruits the main character into this life is totally shallow. Her brain is probably fried from the insane hours she's been forced to keep.
Even that might have been manageable if the story itself was worth the reading but it wasn't. It was so bad that just a couple of days later I've completely forgotten it. They didn't really do anything that a decent drone couldn't have done, so again: point? None! If there had been something - anything in the story to give it some oomph, then the rest of this ridiculous situation might have been overlooked. I can even get with whimsy if there's a compelling reason to, but there really was nothing to see here. I can't commend this garbage as a worthy read on any level.