In a world with lots of magic, there is a planet. Within a rounding error of 1g, sea level atmospheric partial pressure of oxygen about 160 millimeters of mercury, orbiting a G-type star.
The planet at a glance seems to have three continents. One is tropical, overrun with jungle, showing few signs of habitation; a second is half-sunken beneath the southern ice cap, with a small strip of northern coast where it thaws all the way each summer and old-growth forest grows right up to the cliffs overlooking the fjords; and finally, a temperate continent, or perhaps just a large island, dotted with cities.
Some of the cities are bright at night in the manner of human cities, but up north they tend to be dimmer, and shadowed even during the day. The majority of the countryside has been given over to agriculture, a notably small fraction of which is for cereals. Dotting the inhabited continent and parts of the ocean are countless areas that resist scrying; some but not all of them can be seen normally by eye or camera, like the strings of color-changing coins and the things that are not exactly computer screens playing things that are not exactly TV shows. The continent is ringed by islands shrouded in impenetrable mist and shadow; the cities are full of buildings whose windows are always dark no matter that they're otherwise in good repair and dozens of people seem to live in them. Those dozens of people may be predators, possible to mistake at a glance for big cats; they may be hummingbirds; they may be... not quendi, very slightly too short and with eyes set a little too wide and teeth that were never meant for meat. Or they might be four-legged creatures with big eyes in babyish faces and big fluffy tails. Or other things besides those, even, rarely, human.
There are ruins in the solar system. Beneath the ocean of the inhabited planet there are shallows that might once have been continents, things that might once have been cities, and places no one can see into. On the moon there are desiccated bodies, and no sign of any craft that might have brought them there.
Within an hour of any alien craft appearing anywhere in the universe, of course, the imperial government is already trying to scry it.