But, in their original life, the first two both came out in 2000 and this third and final book - Cosmonauts of the Future, Vol. 3: Resurrection - was four years later. So that original audience might have expected, or at least have a reasonable suspicion, that the characters were a few years older this time.
A reader who pays really close attention and has the details of the first two books at his fingertips could have figured that out from the early pages of the book, too - our heroes, Gildas and Martina, are taller, and there's a reference to something "eight months ago" on the first page, an event that didn't happen in the previous books. They also think it's 2033, which would place it more precisely in time if I remembered what year they thought it was in the previous books.
(They are not quite correct, for reasons which become clear as the book goes on.)
They're not on the planet Mawis anymore; they're traveling around in a spaceship, along with two aliens (one in a human suit, their former teacher for killing stinky aliens). They don't say why, but we assume they're looking for the rest of humanity: Gildas and Martina are clones of space explorers who died in a crash on Mawis, and, now that they're growing up, it makes sense that they'd want to find their own people.
They do find a human-crewed space station, which confusingly (for them) seems to be a museum of their lives, exactly like the Mawis-created replica of their childhood that they grew up in. And that's somewhat how this book goes: it's simulacra and clones all the way down.
Gildas and Martina don't learn this for a while - they are very confused, and running about at high speed, often chased by clones of themselves using dangerous weaponry - but they have found human civilization, and it is not at peace. There's a faction run by their daughter Celta and a faction run by Gildas's sister Gaelle, and both use clones of the two of them - the obviously perfect human beings - as soldiers. Both sides are heavily armed; each is dedicated to the extermination of the other; neither is particularly amenable to persuasion or anything more peaceful than a ray-gun.
Do Gildas and Martina manage to bring peace to human civilization, leaning somewhat heavily on the fact that they are "the originals"? (I don't see why their clone-ness is terribly different from the hordes of clone soldiers, but it works, so I won't sweat it.) Yes, they do.
The story is a bit more confused than the first two books, and ramps up the slapstick running-and-fighting material from the second book as well. It does feel a bit like writer Lewis Trondheim and artist Manu Larcenet were escalating with each book, and hit their limit quickly with this third one. It is still fun, zippy adventure, but a reader can definitely see why they would think they'd exhausted the premise by this point.
