Navodno:
It was all a set-up by the CIA.
They spread rumors of something very appealing to a terrorist power (doesn't matter what) circulating in a silver case, a case which they themselves circulated.
De Niro's character, Sam the CIA agent, was there to track the case, which would undoubtedly lead him to Jonathan Pryce's character, Seamus. Sam even says "I'm here for your boss," referring to Seamus. The case is unimportant, and as far as I know, it is never actually opened, on-screen or off.
