Enter the world of VR games in search of your beloved pet! The adventure of Mio and the weakest monster is at your own pace no matter how far you go !? Mio, a girl who wants to keep a pet but couldn't do it because of her residence, decides to play the VR game "magic world online" at the recommendation of her brother. Mio jumps into the game world when she hears that all five senses of the player can be reproduced in the game and can interact with monsters, and immediately tames one monster. However, it was a monster mini slime that was said to be the weakest at the time of the beta test! "I will make this child stronger. I will make it so strong that no one will make me foolish! Because I am Tamer!" The story of a girl who starts an adventure at her own pace with many monsters and players at the first VRMMO.