Bullies often target someone frail and weak—someone exactly like Yûgi Muto. He treasures his Millennium Puzzle, an ancient Egyptian artifact that was brought into his grandfather's game shop. Believing that solving the puzzle will grant him his wish, he completes the puzzle, unleashing a new personality within him, the soul of the "King of Games." The new personality named Yami Yûgi is the exact opposite of Yûgi. Upon any injustice toward him, Yami Yûgi takes over Yûgi's body and forces the opponent into a "Shadow Game".

Izumi was born in a family of celebrities. His father is a singer, his mother an artist, his older brother the lead vocalist for the popular band Crashers. Izumi himself, however, is just a nerdy college student. He loves the manga "Magical Girl Lala Lulu" and dreams of becoming a manga writer himself. One day he is roped into filming a commercial where he wears a dress. Another actor on the set, Ryoma Ichijo, mistakes him for a woman and falls in love at first sight. As it turns out, though, they met ten years in the past. And Ryoma feelings don't change when he finds out Izumi is a boy.

Kang Woo Hyun is a respected anchor at a broadcasting station. He is a devout and happy father, who enjoys being surrounded by his charming family. He decides to try his luck in politics. One day, on a trip he makes with his family, a tragic incident happens. Meanwhile, Go Dong Kook, a veteran detective, who doesn't stop at anything until a case is solved, decides to take the case of Kang Woo Hyun and sets out to investigate what lies behind the tragic incident.

The story begins when the reserved Shizuka attends a local mixer party but has trouble adjusting to the atmosphere. A beautiful older female college student named Ryou starts talking to her, and the pair hit it off. Shizuka goes to spend the night at Ryou's place. However, Ryou unexpectedly kisses Shizuka and pushes her down. Shizuka thinks the beautiful woman is a lesbian but soon discovers that Ryou is actually a man dressed as a woman.