I think pretty much everyone has secretly fantasized about going back and redoing their youth again to take advantage of all their missed opportunities. I'm rather surprised there aren't more manga that deal with the fantasy. The approach taken here is not exactly what you'd think though. It's distinctive because of the very deliberate nature of it. Kaizaki intentionally takes the pill that makes him look (not actually become) 17 and signs up for the program designed to deNEETify him through a return to the optimistic energy of youth. Also deliberate is the time limit of one year: after his year has passed he must return to his adult life where he'll be set up with a job and a chance to reclaim his lost future. All records of his time at school will be erased as will the memories of him among the other students.

I'm of two minds about this as an approach. On the one hand the deliberate nature removes the need for a lot of the confusion about why this is happening (leaving plenty of room for confusion over high school life) and the need for exposition clarifying why he feels obliged to continue acting a high schooler and keep the secret from his friends. The fact that it's not actually youthenizing him also means that there's room for some conflict with the fact that he's not as fit as all the other kids (though really, at older than 27 I might not have the stamina of a teenager but I can still sprint without pulling a muscle) and with all the changes to school life in the decade since he left. And of course the irregular but dangerous moments where his secret maturity seems sure to come out.

On the other hand... aren't the rules here rather arbitrary and absurd? I know that the whole concept is impossible, but making the youthenizing process so mundane as a pill seems even worse than just having it pure magic. It's a lot easier to accept that a wizard did it than that a virus somehow removes all knowledge of someone and can alter pictures. The policies adopted are even more absurd. When it becomes clear that a second test subject has been introduced to the school they make clear that revealing their status to each other would result in mutual memory erasure and ejection. I mean, what possible purpose could that serve? Isn't that sort of connection exactly what they should be encouraging? As indeed they do constantly in amusing ways. And if the goal is to make people care again then why the memory erasure? That seems to completely make any emotional growth meaningless since you know none of your new friends will even remember you. And the fear that this might leave an unbreachable gap in their life is very real, which conflicts with the fact that they want to cure him of a desire to isolate himself to prevent others' suffering. The rules make no sense.

Fortunately, the series is very well written and has a cast of excellent characters. They all fall somewhere on the extremes of academic/social skills. Kaizaki is the most emotionally intellegent guy and also the most utterly incompetent student. Kazu and Hishiro fall at the opposite end of this spectrum, intellectually brilliant but not able to take a hint if you printed it in big letters on your forehead. Everyone else fits somewhere in the middle, with only Kariu having a healthy mix of both. The concerns are mainly those of love (particularly getting the emotional doofuses to recognize their own feelings) and friendship. Typical high school drama fare, but well told and with characters so lovable together that you really root for them. And Kaizaki's (and occasionally his handlers') outrageously brazen matchmaking faces are very funny. The average story arc is very long and takes forever to get to the point, but it doesn't feel padded so much as deliberate. But expect to work though a lot to get to the conclusion of the main arcs.

I relate to this series very deeply on an emotional level. Obviously I never took a de-aging drug and went back to high school, but I did the next closest thing and restarted college in a new degree program where I was 4-6 years older than everyone else. And it was super weird. The insecure awareness that you're several years more experienced than everyone else never really goes away nor does the mistaken belief that you're bound to know more about life than your juniors. In fact it can get worse. By the time I was a 28-year-old PhD student I felt like a creepy old man for hanging out with fresh-out-of-high-school kids in the club I helped run and had to withdraw from all activities. And I've felt the rest of it as well. As an exchange student the knowledge that you only have a year to make friends and then leave them behind forever is always there, a constant awareness that the best year of your life is passing by. It hurts, but only a fool would avoid making the most of their opportunity just so the pain wouldn't be as bad. It's a feeling that's hard to describe but there's probably a snappy German word for it like heiterschmerz.

Anyway, my personal background means that I enjoyed this very much indeed. The inevitable separation in the ending is emotionally crushing as you might expect, and I felt that the arbitrary tragedy of the setting seemed a little forced, but on the whole I cared about the characters and their stories. You just kinda wish they could forget this whole returning to his adult life thing and keep on growing as a high schooler. But the bittersweet setting is the whole basis of the plot, and you get through 215 chapters of sweetness before the end is reached for good so happiness far outweighs the sadness. A good series for anyone who's ever pondered the question of what it would be like if they could do it all over again.