It is difficult to get employment as a werewolf.
Even if you initially manage to keep your condition a secret - a minor offence, under Ministry law - any wizard paying attention will notice a pattern to your monthly "illnesses". The Ministry Register of Werewolves is open, so once they see the pattern, it is only a matter of time until they check, just to be sure, and then you're fired.
No one is quite comfortable working with a werewolf, however meek and mild they are.
It was for this reason that, in that dreadful period between becoming the last Marauder for the first time (betraying your best friend to Voldemort disqualified you from Marauder-ship, he'd decided) and becoming the last Marauder for the second time (Sirius' life was snatched away all too soon by the Veil - betrayal still meant disqualification), Remus Lupin found himself working in the Muggle world.
Muggles, he'd found, would still fire you for missing enough days, but they didn't fling hexes at you for daring to collect your last payslip.
His favourite job in the Muggle world was not terribly surprising: he got a job at a university book store.
(He'd once been called the most Ravenclaw of the Marauders, with his nose often buried in a book, and a propensity for knowing exactly which rules they were breaking now.
That had spawned a series of jokes about whether Peter or James was their Hufflepuff, but it had ended quickly when Peter laughingly called Sirius their Slytherin. Sirius' face had darkened, and Peter had changed the subject.)
Working in a bookstore was always going to be a highlight for Remus Lupin, whose first childhood friends (long before he met three stubborn, big-hearted boys at Hogwarts) had been inked on pages.
But the reason that this job became Remus' favourite, was that it surprised him.
He'd been working at the bookstore for seven moons, a record, even in the Muggle world. He entered to start his shift, the week after the full moon, and came face to face with his manager. She was holding a sheaf of papers. Remus' heart sank when he got close enough to see that they were old timetables.
He could feel his shoulders hunch defensively. He'd had this conversation many times before. He considered reaching for his wand - Confundus charms and Memory charms had extended some of his first Muggle jobs, but it was rarely worth it. The Muggles kept records, so they fired him soon enough.
"Remus." His manager's voice was gentle, as if she felt bad about letting him go. Her compassion was nice, but it wouldn't pay his rent or fill his belly.
"You've missed a number of shifts since you started here with us." She fanned out the timetables, but he didn't look at them. He knew the shifts he'd missed. The dates of the full moon were seared into his brain.
He braced himself. He knew what she'd say next.
"Do you have a chronic medical condition?"
He looked up in surprise. That wasn't what he'd been expecting to hear.
His manager looked oddly guilty. "I don't mean to pry, and you don't have to give me details if you don't want to. But I've noticed that you miss a few shifts every month. Almost exactly four weeks apart each time."
The blood was draining from his face. He could feel it. 'No,' he thought, 'she's a Muggle. She can't know.'
But she was still talking. "I wish you had been up-front about this. We could have worked to accommodate you from the start."
All Remus could do was blink at her.
She laid a warm hand on his arm, the touch both soothing and startling. "If you can, get a note from your doctor. It doesn't need to have a lot of detail, but it should identify that you suffer from a chronic condition, and need time off each month to deal with it. Once that's on file, I can arrange the timetables so you're not working when you expect it to be worst."
It took Remus a little time to gather himself, to remember to thank her properly, to stop staring at her as if she were an angel.
Something was making her nervous; something she didn't want to ask. He could see it in the way she scraped her teeth against her bottom lip; the wolf in him could smell it in the air. He waited.
"I am aware I may have this all wrong," she said in a small voice, "but you might want to ask your doctor…" She fetched a book out from under the counter and offered it to him, the pages held open.
Endometriosis, read the large text at the top of the page.
"I, um, don't want to presume anything. And you needn't tell me anything at all. I don't want to pressure you. But if you're -" her voice dropped quieter, as she said in a rush "- transgender. You should bring this up with your doctor."
His jaw dropped open.
She patted his arm again. "No rush!" she said in a bright, cheerful voice. "Just let me know when you have your doctor's note, when you expect to need time off." She stepped away, then stepped back, awkwardly vacillating. She spoke quickly: "Don't worry. You're safe here." And then she bustled away, busying herself with tidying shelves.
Remus stumbled outside and burst into hysterical laughter. He laughed, and he cried, knowing the jokes his dead friends (and the living traitor) would once have made of this situation.
When he was in control of himself once more, he entered, clocked on, and started his shift. No more was said about it, ever again, even when he presented his manager with the doctor's note.
The manager was eventually transferred to another store. Her replacement was less accommodating. Remus had expected to be fired any day, when Dumbledore sent an owl with dire news and a job offer.