It doesn't take long; the box is light and the currents are strong. Within a few hours, she's hitting the shore again.
This time she's definitely where she wanted to be. She can feel the recognisable cloying taste of the Black Mist around her, and despite it being early afternoon the skies are dark and stormy.
The beach isn't sandy and pretty. It's rocky and bleak and cold, with the biting wind not made any better by the perennial wetness of the more mundane kind of mist that also seems to be everywhere. The ruins of a port city she might recognise surround her, with glowing green-blue wisps of magic keeping debris and even entire ruined buildings afloat here and there. There's enough light from the Mist that it should probably have been named the Green-Blue Mist, not the Black Mist, and it is enough to see by even with the sun entirely hidden.
And of course, here and there, the dead.
There's not an army, nor even groups, for the shambling corpses will turn on each other when lacking other prey. People, their bodies not entirely rotted away as the Mist reanimates them too quickly for the rot to properly settle, but dead nonetheless. Not doing anything, really, just standing around, looking agonised, occasionally staring at bits of architecture and having fits of despair that express themselves as loud keening wailing that can be heard for miles. It happens enough that the background noises are entirely dominated by those wails, most of them from unseen sources in the distance partaking in their own brand of suffering.
But the sight isn't as ghastly as that of wights, ghostly creatures that used to be spirits of all sorts, distorted by the Mist into mockeries of their former selves. Their forms shift chaotically, at times expressing memories of death and horror played on repeat before recoalescing into individual shapes. They make no sounds, but their pain is felt nonetheless.