One of the key secret supernatural powers of the Adjustment Bureau, a shadowy sect from the mists of time that keeps a weather eye on man's follies, is....hats. Preferably trilby hats.
They're worn by ranks of Bureau agents as a means of getting through doors that don't lead where you expect. For instance, a bathroom in a downtown Manhattan ballet company leads to... the pitch of the New York Yankees.
And, suitably hatted, when you leave via the exit of the Yankees Stadium, you find yourself emerging onto Liberty Island, smack-bang in the middle of New York harbour.
Trilby-assisted travel is not the only occupation of the Bureau. Oh no. Since time began they're kept a benign watch on humanity, clandestinely intervening when things went a fatefully off-message. The Great War, fascism, the Holocaust, that sort of thing.
They have to step in when ambitious American politician-on-the-rise David Norris (Damon) meets struggling contemporary dancer Elise (Blunt) on a bus travelling through Manhattan.
This wasn't supposed to happen...but Bureau operative Andrew Mackie nodded off on a park bench and allowed Norris to get to Elise's number after the two had briefly met while Norris was on the campaign trail.
Time-shifting into sci-fi mode, Norris is immediately grabbed by Bureau goons and grilled in an underground car park by Mad Men's John Slattery who tells him his literally ill-fated second meet with Elise has to be his last. But Norris is smitten.
Less hard-boiled thriller and more romantic sci-fi fantasy, this is keep afloat by the zinging chemistry between Blunt and Damon, perfectly illustrated in a terrific scene where they meet for the first time in the men's room at the Waldorf Astoria.