"Just get in the car, Javert!" Valjean says urgently.
Javert has known the demon Valjean  for 6000 years and has never seen him look shiftier. "You are up to something."
"I'm not up--" Javert fixes him with a withering look, and Valjean manages to look sheepish. "You know me too well. Look, you'll come around to agree with me before long anyway, couldn't you try just... trusting me?"
"Whenever you ask me to trust you, it means you've done something especially rash," Javert complains, but he is already following Valjean, his sensible heels  clacking as they stride down the walk... and making a mental inventory of what possessions of import he's left in the Thenardier mansion. If Valjean says they need to leave together, then he needs to leave, whether he ends up agreeing with Valjean or not -- a thing that has happened more often than it ought, particularly in the last two centuries or so. 
Valjean's Citroen  is parked on the side street, as inconspicuous as a mint condition vintage automobile can be (which, in this neighborhood, is considerably more inconspicuous than usual), already running. At least it will not automatically be tied to either of them, since 'Brother Fauchelevent' drove a dumpy turn-of-the-century Renault, and Javert avoids driving whenever possible, as a matter of principle, no matter what sort of persona is called for.
He gets in the car against all his better judgement, smoothing the line of his pencil skirt as he swings his legs around. At least now he will be done with--
"Oh," says a soft, girlish voice from the back seat. "Governess, you're coming too?"
Javert cannot breathe. 
Cosette is in the car. Cosette, the Antichrist , is in Valjean's car. The car in which Valjean wants to leave immediately... with Cosette in it, Javert assumes, which is why Valjean wanted him to hurry, and oh, Hell, he'd never anticipated this, not even in his wildest imagining of 'things Valjean might do'. 
"If you're coming with Papa and me, are you... going to be my Maman?" Cosette continues hesitantly.
Even Valjean cannot keep his composure at that, and splutters helplessly. "I-- that is, we-- he-- she--"
Javert, completely flummoxed, stops time with a sharp snap of his fingers.
"We are friends!" Valjean blurts out, incognizant of the fact that Cosette can no longer hear him, and Javert stares at him incredulously.
"Friends!" Javert thunders, until he catches a glimpse of the child in the back seat, frozen in wide-eyed inquiry, and the absurdity of his being friends with a demon is forgotten as a distraction from the real problem at hand: "Valjean, you can't steal the Antichrist!" 
"Surely after six millennia you can admit that we are friends," Valjean says, a bit wounded.
"That's not the point! There is a child in the back seat of your car, Valjean; what do you know about really taking care of a child?"
"A damn sight more than M. and Mme. Thenardier, that's what," Valjean growls.
"I cannot argue with that," Javert admits. "But neither my superiors nor yours are likely to be swayed. We could both be in danger if anyone on either side realizes that we-- that you have just... run off with the Antichrist."
"We don't even know that she is the Antichrist. She's still never shown any sign of... powers." 
"Even if she isn't the Antichrist, you can't just kidnap a human child because you don't approve of her caretakers. They will go to the police, the media--"
"I could make them forget they'd ever met her. I should."
"Valjean... for Heaven's sake, be realistic, what are you going to do with a child?"
It washes over him like a wave, the fierce and protective love Valjean feels for the girl, and he can't breathe again; he can't think; he doesn't dare look any deeper than that. God above, what is he doing, what did he ever think he was doing cooperating with a demon, even Valjean? Especially Valjean. Maybe Valjean is the worst of the lot, because it's not as if any other demon has ever stood a chance of getting him to doubt, or to break the rules, and Valjean... Valjean just turns everything upside down. Whenever he's around, things he had always thought were simple seem complicated, and things that he was sure were complicated seem so simple...
Valjean loves Cosette, not just as he's always cared about humans in ways Javert struggles to, but also personally. Demons aren't-- they don't-- well, Valjean has always been a piss-poor demon anyway, but he's still a demon and anyway the point is--
"Valjean, I-- we-- I don't know what you're planning to do, but I can't just go... shacking up with a demon!" he finishes, flustered.
"I haven't asked you to."
"I mean, I-- what?"
"You don't have to come with me. With us. I know you didn't-- this wasn't your decision, and I don't expect you to..." Valjean trails off, subdued and a little bit lost, nothing like the fervor with which he declared his love for the child a moment ago. "...to do anything so obviously not sanctioned by... anyone up there. You would never, I'm sure. I just didn't want to run off and leave you to clean up my mess with no warning."
"Uh, yes. Right. Polite of you."
"You could, though. If you wanted to."
"If I wanted to what?"
"Come with us. If you wanted to."
"I..." Javert can feel his resolve crumbling. He has no idea what he's even trying to do here anymore. "You know, I don't even know whether I would get in worse trouble for going with you, or for knowing it was happening and not going with you."
Valjean's expression brightens alarmingly. "What if she's not the Antichrist after all? Come on, angel, surely you can't allow a defenseless child to live with a demon."
"I thought you weren't asking me to go with you." He glares at Valjean, but there's no heat to it. 
"I just want to be sure you consider all the, uh... considerations... that Chabouillet would expect you to consider when deciding whether you should shack up with a demon."
Javert buries his face in his hands. "I suppose someone is going to have to make sure you don't spoil the child rotten," he mumbles.
Valjean doesn't even say anything, the bastard, probably because he knows he's won, and by the time Javert looks up again, he's looking a bit impatient. "If you could," he says, gesturing at Cosette frozen in the back seat, "just pick up where we left off?"
Javert can pick up where they left off, all right. He snaps his fingers again. "Cosette already knows her pronouns very well," he says drily, of Valjean's spluttering. "I am not... suited to motherhood. But I will be coming with you, and you may call me Javert, since I won't be your governess any longer."
"Oh," Cosette says again, her eyes very round.
Damnit, he's either going to have to stay in this shape or figure out how to explain returning to his usual corporation, he's probably going to have to call Valjean 'Fauchelevent' for another half a century or more, they're both going to have to do things the human way if a clever child would notice a miracle...
"I'm glad," Cosette says after a moment, decisively, and Javert's heart seizes up and sputters like the engine of Valjean's decoy Renault.
"So am I," Valjean murmurs, which at least does not cause any reaction Javert wasn't already experiencing.
"We had best get on our way," Javert says curtly, ignoring the way his heart feels too big for his chest, and opening the glove box to flip through Valjean's CD wallet.
"I'm afraid all of them have been in the car for more than a fortnight," Valjean says as he starts the engine.
"Hell," Javert complains, but he puts one in anyway, and as Valjean hits the gas and takes Cosette away from the Thenardiers forever, the Orchestre de Paris performs Faure's Sigh No More.
 There are few now who have not heard the story of how, in one particular universe, the angel Aziraphale and the demon Crowley came to an Arrangement that eventually helped avert the apocalypse. There are many similar universes, in which the breeze generated by the wing of some drunken butterfly caused some slight change -- the color of Crowley's hair, perhaps.
Three universes to the left, however, a very different story unfolded, as the angel assigned to the eastern gate had no interest in either talking to serpents or showing mercy to humans who had been given one law and immediately broken it. The angel of the northern gate, on the other hand, was so filled with concern for their plight that he stole some manna from heaven to give them to eat. This was almost immediately discovered, and he was cast down from Heaven.
 It had not even taken a miracle, only the right conversation overheard in the grocery, to convince Mme. Thenardier that her three small girls ought to have a governess. The miracle had been saved for introducing a typo into the contact information in her job posting after it was already online, so that the only respondent was one Mlle. J. Verte. As she happened to be eminently qualified, she was hired before the error was even discovered.
Mlle. Verte habitually wore a grey power suit with a pencil skirt. Her face was sharp and severe, a fact only amplified by the fact that she wore narrow tortoise-shell glasses and her hair was always swept up into an impeccable bun. If anyone had ever coughed discreetly and muttered that she might be the sort of nanny who advertises unspecified but strangely explicit services in certain magazines, they would have been laughed out of town.
The gardener, Brother Fauchelevent, had arrived the same afternoon. M. and Mme. Thenardier's garden had never been so lovely.
[a] Javert does not particularly care to discuss June 7, 1832, or in fact 1832 at all. [b]
[b] He would now most likely deny that he had actually had a crisis of faith after a demon [c] rescued him from the revolutionaries who planned to execute him, sparing him a painful and inconvenient discorporation, and he would certainly deny that a demon [d] had talked him down from it, but since shortly after that date they have had a certain Arrangement... which is how Javert ended up in his current predicament.
[c] That is to say, Valjean.
[d] That is to say, Valjean.
 Ignoring, of course, the fact that it is patently obvious that Valjean can; the real issue is whether he should (absolutely not), whether he is going to (apparently yes, damn him to Hell (again)), or perhaps whether Javert can cope with it if he does (absolutely not, except for the part where he might not have a choice about it).
[a] For absolutely no good reason, since he is an angel! It is clearly Valjean's fault. Somehow.