The prince was an athletic young fellow, climbing walls and jumping between buildings, in a manner reminiscent - not of the Prince of Persia game franchise - but of the hero Altair from Assassin's Creed, with some shots being direct homages (read: ripoffs).
The olden days of yore in Persia was a wondrous period, filled with hammy acting, crappy CGI, and Persians who speak Arabic instead of Persian (save for the main characters who speak Queen's English).
But it was also a time of great peril, with one of the greatest dangers being a clan of wizard ninjas called "Hassansins" (not a typo) - predating the existence of the real Hashshashins by roughly 1500 years.
One day, for reasons which are not entirely clear, the prince and his royal family invade a sacred city. There he comes across a young princess with full, luscious lips and annoying voice, and the two embark on an adventure together.
Sparks fly between the young couple. Well, not the young couple of *this* film, but the one from the Pirates of the Caribbean franchise - something which this movie desperately aspires to be. The couple in this movie has the chemistry of a vacuum, and the screen fizzles as they deliver their supposedly witty banter.
They charge to and fro in the Persian country side, bumping into comedy sidekicks and gallant black men who (of course) die first.
The couple is trying to stop something, which isn't entirely clear, from happening. Or are they trying to make something happen? The viewer can barely remember, as he couldn't care less by this point.