Meet Lisa.

It's late. The floor lamp casts a warm circle onto the sofa, and Mara only meant to read one more chapter of “Das Fahrwasser”. Now she is deep in Stefan's story. The display on his wall shows 38 degrees, in the middle of May, water drips sparingly from the tap, and Stefan drives his car to the park, not to go for a walk, but because the car has something to give there.

Mara can almost feel the heat herself. Her eyes follow the lines as if spellbound. At the edge of the park, Stefan connects a hose to his car, and the drinking water the car made from salt water on the way flows into the irrigation. Mara sees the park as clearly as if she were sitting next to Stefan by the pond.

Mara turns the page. And stops. A car that fills up on salt water and keeps a park alive with it. Does that exist? Or is it made up? She realizes she simply believed it. The images in her head were so vivid that it never occurred to her to ask.

One question remains. Mara pulls up the panel at the bottom of the screen and types it in. The AI assistant knows the book and answers. All the while, a small note tells her which AI her messages are sent to for processing. That gives her a good feeling.

Mara puts her phone aside. She should have gone to bed long ago. Just one more chapter, she thinks. Stefan is still sitting by the pond, his car is still giving its water to the park. But now Mara reads the scene with different eyes. She knows which part of it is fiction and which is based on research.

The hall is loud. People push past the booths, stop for a moment, move on. At the Mercedes-Benz booth, Lukas is standing at a very special, large table. Behind its digital surface, a virtual city unfolds. Streets, intersections, parking spaces. And the small model car standing on the screen seems to be driving through exactly this city and its challenges.

Lukas is 31, a development engineer by trade, and today he's an explainer. His job is to show visitors what the car's parking and driver assistance functions can do. He enjoys it. He likes explaining things and believes we can only learn from each other.

One year later.

A new trade fair day, and just like last year, a new group crowds around the large displays on the table. This time, Lukas simply puts the token, which last year he only used for pausing or fast-forwarding, down on the screen right where he is. The menu now opens around the token, right in front of him. A few moves, and the parking scenario has started.

The visitors follow what he's doing. The circles move around the token, which is modeled on the Mercedes star, and icons and images show where things are going. No one has to guess what's happening.

It's Sunday evening. Nele has rolled out her mat in the living room and dimmed the lights, and her yoga flow is playing on her phone. Downward dog. Breathe in deeply.

Then the next song. It doesn't fit at all. Nele comes out of the pose, crawls over to her phone, taps, searches, taps again. By the time she's back on the mat, the calm is gone.

Later, during meditation, a notification cuts across the audio. An earbud has disappeared somewhere between the mat and the rug.

The music is too loud. Nele taps the side edge of the mat and slides her finger down a little. Quieter. It doesn't matter exactly where she taps. The slider measures from the point where her finger lands.

For the dance part, Nele doesn't feel like searching through a playlist. On the right of the head end, there's a small field. She drums the rhythm onto it with her fingers, the one that's in her head right now, and SMAT suggests a track with exactly that tempo.

It's Saturday night, just after eleven. Jana's tea has gone cold, and she's about to go to bed. In the kitchen, she notices that Kira hasn't touched her breakfast, and she never does that. Jana last saw her at 7:40 a.m., on the windowsill in the hallway. Now the balcony door is open a crack, and the apartment is silent.

Jana calls her name, first in the stairwell, then in the courtyard. Nothing. She goes outside and tries again, in vain. After an hour, Jana unlocks her phone with shaking hands. A few months ago, on a quiet evening, Jana had installed Pfotenspur. She had uploaded photos of Kira, typed in “gray tabby, white paws, kink in her tail” and marked two favorite spots on the map: the neighbors' shed and the hedge by the playground.

Two streets away, Marie gets a notification. She sees it the next morning when she glances at her phone over coffee. Marie doesn't know Kira, and she only has a few minutes. The app doesn't expect more from her: she's asked to check her own garage and basement, about two minutes. Plus the note “Shy: don't touch, just report”.

Marie takes a look. Nothing. She taps “Checked, no trace”, without an account and without giving out her phone number. On Jana's map, point five turns green.

At 2:32 p.m., someone from the neighborhood reports in: “Gray cat under a carport, heading toward the playground.” The sighting appears as a dot on Jana's map, 120 meters away. Jana checks the photo. Kira's white paws, that fits. She writes in the chat: “Please don't touch her, I'll be there in five minutes.”