When Miki Koishikawa welcomes her parents home from their trip to Hawaii, the last thing she expects is for them to gleefully announce that they are getting a divorce. To her shock, they plan to switch partners with another couple they met on vacation. Barely able to keep her emotions in check, Miki begrudgingly attends dinner to meet the other couple and their strikingly handsome son, Yuu Matsuura.

After moving into a spacious house with her newly blended family, Miki struggles to adjust to her new lifestyle and her blooming feelings for Yuu. She attempts to navigate the coming school year with the help of her best friend, Meiko Akizuki, who is hiding a scandalous relationship of her own. However, the road ahead is not simple, as both Miki and Yuu have other potential suitors and emotional baggage from their pasts they are reluctant to reveal.

Marmalade Boy received a Taiwanese 30-episode live-action television series (called Júzǐjiāng Nánhái). The series starred pop star Stella as Miki and F4 member Ken Zhu as Yuu. Although the basic premise was the same, it did not feature many of the characters of the anime, and the love triangles were considerably simplified.

It also received a dating simulation video game was released by Bandai Entertainment for the Nintendo Game Boy system in Japan on January 1, 1995. It was released for the Super Famicom (Super Nintendo) system on April 21, 1995. The game puts players in the role of Miki, who must try to win the heart of one of her three potential suitors from the series: Yuu, Ginta, or Kei.