Lin Eun is a professional gamer who has been recruited to a game tester team for "The Last Step," a virtual reality game.

One day, a big fire breaks out in the company building.
To save a team member trapped in the game, Lin goes through the fire and logs onto the game.

When she wakes up, she finds herself in the body of Princess Adriel, an NPC inside the game.

"How have you been, Lin?"
"This can't be real... How are you here?"

Siheon Ryu, the leader of the medical team, also gets trapped after following Lin into the game.
Inside the game, he is another NPC named Richard Blanc Tesca, who is Adriel's fiancé.