Fans waiting for a sequel to " Percy Jackson and the Olympians: The Lightning Thief " may not have to wait that much longer. LA Times is reporting that Fox 2000, the 20th Century Fox label behind the adventure franchise, is putting a follow-up project to the 2010 young-adult film in active development and could shoot it as early as this summer, according to a person who has been briefed on the project's status but was not authorized to speak publicly about it. The movie would be subtitled " The Sea of Monsters " and derive from the second book in Rick Riordan's five-book series. The studio has hired Scott Alexander and Larry Karaszewski -- who wrote "Ed Wood" and "Agent Cody Banks" -- to write a script for the new film, which they are currently doing. But the person cautioned that the project is still very much at the development phase; the movie, for instance, does not yet have a director. Chris Columbus , who helmed the first ins