David O. Russell calls from his editing room to chat about I * Huckabee's, in which Lily Tomlin and Dustin Hoffman play a team of ''existential detectives.'' Pardon? A team of what? ''Somebody you hire to investigate your life. Or some situation in life.'' Oh. Right. Russell can tell you that -- like his farce Flirting With Disaster (1996) and his Gulf War black satire Three Kings (1999) -- it is a comedy. He'll allow that Huckabee's is a chain store through which an intriguing ensemble passes: Jude Law, Naomi Watts, Mark Wahlberg. Yet he cannot bring himself to explain what his movie is about. ''Can I think about it?'' He calls back 24 hours later. He has not slept. ''We were just cuttin' round the clock, man. Inspired and it's good.'' Great! So what exactly does an existential detective do? ''It's just too hard,'' he says. ''I would give it away.'' Such is the pitch for a mystery.