Night is falling in New York City, and as the lights in the skyscrapers go on, the workers prepare to return home. But suddenly the lights go out in one building, and inside the staff wander around in the dark wondering what to do next, for the elevators are not working either; some take the opportunity to have some fun, and decide on a so-called Braille party where participants can divert themselves feeling their way around, but for David Stillwell (Gregory Peck) he is not so keen, and leaves them to it to try for the stairs. Once there, using his pen flashlight to see, he hears someone approaching from above: it's a young woman (Diane Baker) who seems to know him, though he does not recognise her, and as they descend she begins to act very strangely...
It might be accurate to observe that Mirage started with its best sequence, establishing its mystery then winding down over the course of just under two hours to when all was revealed, but what an opening it was, genuinely intriguing and novel. It was successful because we take it as read that Peck, one of the most dependable presences in his era of film, knows exactly what he is doing and why he is in that business block, but soon after all that is thrown into doubt by his meeting with Baker's stranger and, after she gives him the slip, the realisation once outside that there has been a terrible incident as a man has taken a fall from one of the upper floors and died in the impact. But did he fall or was he pushed?
When Stillwell discovers that this dead man was well-known philanthropist and international peacemaker Charles Calvin (Walter Abel), he feels he has a connection to him, but how? He is, after all, a simple cost accountant and has worked in the same office for the past two years, so why does he now sense there is something not right in his world? Why do people he thought he knew barely recognise him? Does he have amnesia? Would that explain why he is suddenly on the wrong end of a gun held by Jack Weston? In one of many bizarre touches designed to disorient the viewer, once they get back to David's apartment the heavy insists on watching the wrestling on television instead of informing him what he actually wants.
The structure was something akin to a detective story, though every so often the hero has flashbacks to what has happened before as he tries to piece together his recent life that seems to have escaped him - but if you watch closely, you'll notice one image that we have not been privy to, and is going unexplained. After getting the advantage of Weston, he settles on being more proactive and starts doing his own detective work, visiting a famed psychiatrist (Robert H. Harris) who once he hears of his condition - a lapse of memory lasting a couple of years - throws him out of his office in disgust, believing Stillwell to be faking it for his own prankish motives. Back to square one, he notices an actual detective agency run by Walter Matthau and drops in to see if he could help, Matthau offering one of many almost quirky readings in the film.
The story was wrapped up in memories and how they make us what we are, asking if we no longer are aware of what has happened in our pasts, if indeed we were ever aware, does that make us a different person to what we thought we were, or what others believed we were. Peck was ideally cast in what from some angles might have looked like a revisit of his character from Alfred Hitchcock's Spellbound, just stuffy enough to convince himself he could have been a grey-suited accountant all this time, but given some nice lines by Peter Stone's pleasingly witty script and playing off his fellow cast, Matthau in particular, with aplomb. Once that enigma is cleared up, it was true to say Mirage lost some of its power, but there was a conclusion that told us it was important to remember how fallible everyone can be, from the great men to the lowly, wrapping up the thriller with director Edward Dmytryk building to that skilfully. All in all, if a shade overcomplicated in matching the mystery to the near-science fictional explanation, a satisfying suspense work. Music by Quincy Jones.