The National Treasure films weren’t good by any conventional definition of the word, but they were fun. After all who doesn’t love a globe-hopping treasure hunt—especially when it comes wrapped in a conspiracy and painted over with a few layers of historical significance? Just ask Indiana Jones. Or Tom Hanks in that Da Vinci thing. These clue-dropping treasure hunts aren’t something episodic television has had much luck recreating. But ABC’s new thriller “Zero Hour” certainly gives it the old college try. And if the pilot episode is any indication, the network might have something halfway decent on its hands.