Oh my goodness. This is a lovely, lovely fic, witty and charming and perfectly paced and streaked with shadows of oncoming tragedy that touch the edges but don't overpower the mood. The landscapes and atmosphere are beautifully evoked, the stillness and solitude, the ice-cold lake, the perfume of elderflowers that smell like childhood.
It was a fantastic idea to set it in Augusta's irascible and somewhat self-centered POV. Her impatience and sharp opinions, her position outside the circle of those who know what's going on, her nagging worry about those dear to her in the firing line, her loyalty to Minerva (not to mention her role as Minerva's partner in repartee) are endearing and just a little bit maddening. I was also delighted by the liaison between Amelia and Severus, their bonding for mutual benefit over herbs and sex, and the way Severus blossomed just the tiniest bit under the positive attention (although I was reassured by his snotty remark about varicose veins that he hadn't gone soft). And Augusta practically pouncing on Minerva in the camp bed after her spot of accidental voyeurism was realistically sexy: rushed and cramped, and with that lovely line about the little gems of dirty talk spilling from Minerva's lips. All the details are bewilderingly good, conjuring up place and circumstance, that odd cross between holiday and undercover mission, and the way groups of (more or less) friendly strangers negotiate close quarters. Stinky Bob and St. John's Wort. The potted shrimp. The portable cauldron. The tree that's probably as old as Dumbledore. Severus hiding his face from the Death Eaters, trapped and terrified and probably getting a lesson in how deadly his erstwhile friends can be.
The story is chockful of quotable lines, so I'll just have to flail my hand at the whole thing and beg others to read it. Your delivery is priceless, always perfectly on the beat. You have such extraordinary confidence and concision at scene-setting that I can only be jealous. And oh, the pang of knowing the fate that lies in store for most of these characters, which makes their short-lived respite, these glimpses of who they might have been if the war hadn't required their sacrifice, all the more precious.
Frankly, dear author, this has been a shitty day, and your story has lifted me out of my funk and made me surprisingly happy. You have an amazing talent, and I'll return to this fic over and over for the sheer pleasure of it. Brava!