What is Sony's mystery E3 game?

The BBC is teasing that mystery Sony game yet again. When BBC's Darren Waters first described this mystery game, he noted that "we could be on the brink of a step change in what games consoles are capable of in terms of story-telling and immersion." However, Waters was surprised that they did not show this game. MAG was cool, yes, but it was not the game this BBC writer was teasing. "This was not the game I was referring to ... And so I still can't talk about it. Or even tell you what it's called."