The PSP version is a side-scrolling 2.5D platformer that roughly follows the same style as the other versions. It has a different storyline involving freeing the sisters of time, and a different antagonist.
The PSP version features a plot in which the prophecy is written that a member of Prince's royal family will bring end to an evil fire spirit Ahihud's dark reign over hidden mystic land. To ensure his survival, the evil spirit's minions hunt down those with the royal blood. Prince escapes his tower, where he is kept protected by his father, and pursues a mysterious guiding light, which turns out to be Helem, a spirit of time who promises to help the Prince defeat his enemy.
PLOT
The Forgotten Sands returns to the storyline established by Prince of Persia: The Sands of Time, and concluded by Prince of Persia: The Two Thrones.[11] On December 14, 2009, Ubisoft UK released the first details of the story on their official video portal.[12]
The game is an interquel, taking place in the seven year gap[13] between Prince of Persia: The Sands of Time and Prince of Persia: Warrior Within. The Prince character is supposed to be a cross between the character models in these two games. Once again he will be voiced by Yuri Lowenthal.[14]
The plot of main game, developed for PS3, Xbox 360, and PC, begins as the Prince is riding through a desert on his horse, on a quest to see his brother, Malik, and learn about leadership from him. When the Prince arrives at Malik's kingdom, he finds it under attack by an army who he proposes wants a treasure buried deep within. The Prince infiltrates Malik's kingdom, and meets up with Malik in the treasure vaults.