On the day of Astrid's birthday, she came across a full body size mirror inside her apartment that she thought was a gift from her friends. She was about to set it aside, but when she touched it, the reflection changed into a different place. Astrid was intrigued, curious, she took a look at it again and bowed herself to see it in detail. But when she was about to stand up, she lost her balance and fell inside the mirror. When she woke up, she's in a different world and was assigned as a guardian, an heir of a goddess on one of the country's region she fell into.