An office worker collapses from overwork and then wakes up to find that she's been reincarnated into the world of her favorite video game, "Starry Love Astrolabe".
Diana, who knows the truth of the game, struggles to keep Sirius at arms length. If Diana and Sirius get serious, it will lead to the game's bad ending.
Though Diana has mixed feelings about her relationship with the Prince, she still doesn't want the bad ending to occur. Wanting to find answers, she decides to visit the place where they have shared memories together.
A mysterious coded letter arrives and confuses Diana. Disregarding the letter, she tries to get some sleep and upon waking she's met with a mysterious stranger in bed with her. Is this the route to the bad ending?
Diana is imprisoned by Spica. Upon searching her cell, she discovers Diana's Diary. While reading it, shocking truths are revealed. Meanwhile, the Prince is trying to find out what happened to Diana.
Diana is freed by Prince Sirius. They begin to explore their feelings. Meanwhile, Spica laments his punishment for the damage done to free Diana. New information is told by Manservant about the Prince's fiance'.
Diana is in love and tells herself that this is her last time with the Prince. The next morning, Diana tries to tell Sirius that she will keep her distance from him, but suddenly Spica and Manservant barge in.
Realizing that she's been caught, Diana confesses the plot. Expecting to be banished as an appropriate punishment, the Prince instead makes a surprising offer to her.
