Mirage (1965)

"RUN... Right Into Her Arms... Perhaps She'll Lead You to Your Lost Secret... Or Into the Arms of Peril!"

After a blackout in his office building, accountant David Stillwell emerges outside to find out a man he did not know either jumped or was pushed out a window to his death — and that he can't remember the past two years of his life. Enlisting the help of a rookie private eye and a reluctant old flame, Stillwell uncovers the mystery detail by unexpected detail.