5. National Treasure: Book Of Secrets (2007)
Perhaps an unlikely hit, National Treasure seemed at one time to be the heir to Indiana Jones‘ throne as the big historically-driven action-adventure franchise. With Nicolas Cage leading the charge, National Treasure‘s success was followed up with a sequel, subtitled Book of Secrets, just two years later. The film continued the story of Cage’s Benjamin Franklin Gates as he investigated conspiracies surrounding items and people of historical importance.
Book of Secrets ends with a tease of a particular page of the titular book (which belongs to the President of the United States of America, no less). The exact conspiracy or treasure that the page concerns isn’t revealed, but it does serve as a sequel tease, providing a narrative avenue into the third National Treasure film. Sadly, that threequel was not forthcoming.
Talk of National Treasure 3 still survives, and every so often a vague update is offered that doesn’t encourage much hope. The franchise is being given a Disney+ spin-off series to which Cage seemingly has no attachment, and though scripts for National Treasure 3 have been bouncing around for years, Disney reportedly aren’t happy with them. This makes National Treasure: Book of Secrets‘ sequel tease ring hollow, as it would seem that National Treasure 3 is stuck in development hell.