\"The Quiet Earth\" (1985)

Scientist Zac Hobson wakes up in the morning and sooner he finds that he seems to be alone in the world. He drives around unsuccessfully seeking out other survivors and tries to figure out what might have happened. After a few days, he shows traces of insanity due to the loneliness. Out of the blue, Zac finds Joanne and they stay together looking for survivors. Zac meets the distrustful black Api and Zac explains that he believes that the project that he was researching in the government laboratory might have caused the phenomenon. Now the trio decides to blow-up the laboratory to stop the experiment.