Wizard and the Princess, also known as Adventure in Serenia, is a 1980 computer game by On-Line Systems for the Apple II and Apple II Plus. It is the second title released in On-Line Systems' "Hi-Res Adventure" series after Mystery House. It is a prelude to the King's Quest series in both story and concept.
The game takes place in the land of Serenia where King George's daughter Princess Priscilla has been kidnapped by an evil wizard named Harlin. Harlin has held her inside his castle far in the mountains. The King has offered half of his kingdom to anyone brave enough to travel to the Wizard's castle, defeat him and return his daughter. The player assumes the role of a happy wanderer who answers this challenge.
When released for the IBM PC as Adventure in Serenia, the plot was described as if it were a sequel to Wizard and the Princess (although the game itself was no different): some time long into the future after Harlin had been defeated by the Wanderer, he challenges an adventurer to repeat the actions of his previous defeat. He turns back the sands of time leaving the adventurer in the village of Serenia. He mocks the hero telling him that he may have been defeated once, but he couldn't be defeated a second time. The princess gives hero some words of advice and a computer to help him defeat Harlin the second time, and tells him he has become the wanderer.
As with the previous game Mystery House, Wizard and the Princess was distributed by Roberta and Ken Williams company On-Line Systems in plastic bags with the 5 1/4" floppy disk and instruction sheet. The instruction sheet had the title listed as The Wizard and the Princess.
The story was based on the many fairy tales Roberta used to read as a child. The game improved upon Mystery House by adding color graphics. It was the first adventure game to have color graphics and sold over 60,000 copies. The Apple II could only display six different colors simultaneously, but clever use of dithering made it possible to give the illusion of more colors on the screen.
Wizard and the Princess was also released for the Atari 400/800, Commodore 64 and the IBM PC. Roberta Williams disliked the IBM PC version titled Adventure in Serenia because she felt the colors looked "atrocious".
According to Sierra's Interaction magazine, this game can be considered a prequel to the King's Quest series. King's Quest V marked a return to the Kingdom of Serenia. The events are mentioned and expanded upon in The King's Quest Companion, 2nd Edition. It mentioned that the wanderer, a barbarian, had turned down the offer of marriage after saving the princess. He journeyed into the desert and died. All that remained of him is his skeleton and a single leather shoe (A reference to KQ5). Princess Priscilla later married an individual named Kenneth the Huge and became the queen of Serenia, after her father's (King George IV) death. It was further referenced as part of the King's Quest series through a trivia question in the King's Questions game that came with certain versions of the King's Quest Collection.