The Subway I Built Leads to Another World

After finishing her shopping, Yun You took the last subway home. The carriage was empty, with no one else inside.

At the next stop, the doors opened. A wounded woman dressed like a mercenary stood at the entrance and pulled a packet from her pocket. "Do you have any food? I'll trade you this bag of super seeds for some."

"?" Was she cosplaying?

Yun You played along and handed her some bread. "Hey, can I take a picture with you?"

The mercenary nodded, looking completely bewildered.

After the photo, Yun You got a packet of seeds that looked like props.

The subway stopped again, and the doors slid open.

A group of black-robed people were kneeling outside. They called her a god and begged her to grant them the seeds that would save the world.

These black-robed people, who called themselves wizards, took the seeds and offered her a horned Abyss Cat and two chests of gold.

Yun You: "..." I must be taking the subway wrong.

The subway doors opened and closed. People got on along the way and went adventuring with Yun You, while others got off and stayed forever in some other world.

By the end of her journey, Yun You had acquired all sorts of titles: savior of a post-apocalyptic lord, god of salvation, the greatest witch in history, the secret owner of an interplanar supermarket... The contents of her shopping bag had also changed to super seeds, miraculous potions, a portable storage space...

Theme: Interplanar trade