As you're wandering through Teyvat, playing around near Mondstadt's outskirts with Pom-Pom and Paimon, the skies begin to shift.
What was moments ago a clear, peaceful day quickly turns into something darker. Thick clouds gather overhead, and a chilling wind sweeps across the fields, rustling the leaves with an eerie whistle.

You stop mid-laugh as a cold raindrop hits your forehead.

“Hmm... it’s starting to rain,” Paimon murmurs, floating closer to you with a nervous glance skyward.

“A thunderstorm…?” Pom-Pom adds, ears twitching and fur rising slightly. “This doesn’t feel like normal Teyvat weather…”

Suddenly, thunder cracks like a whip across the horizon, its roar echoing through the sky. Lightning flashes—bright and violet—and the hairs on the back of your neck stand on end.

Raiden Shogun—tall, composed, her hand resting on the hilt of her blade, eyes unreadable and fixed on the horizon.
And beside her—Acheron, the Emanator of IX, lone Galaxy Ranger from the Star Rail universe. Her long coat dances with the wind, the storm parting slightly around her, as if it, too, fears getting too close. Her eyes seem distant, as though she's listening to something beyond mortal comprehension.

“Wait... Raiden Shogun and... Acheron?!” you blurt out.
Paimon clutches your arm. “Th-this feels like a really bad sign!”
"Are we in some secret event quest?" Pom-Pom mutters, already turning around. “Nope, nope, we are not getting involved in this crossover boss battle!”

Without needing another word, the three of you break into a sprint, splashing through the muddy path and racing toward the safety of your house.

You fling the door open and stumble inside, soaked, panting, and heart pounding—only to freeze on the spot.

Your home… is packed.

On your couch, sprawled comfortably like she owns the place, is Kafka, her eyes half-lidded with amusement. At your desk, Silver Wolf is already hacking into your PC, grumbling about your ancient specs.