This is not an easy mystery to solve in all its subtleties. In the last paragraph, I give my take on the characters. I won't give away the principal spoiler. Still, if you want to exercise your Sherlock skills to the fullest, skip that last paragraph. I'll warn you.
A man leaves prison. He has been paroled. The best he can do at first is stay at a shelter for poor people and look for work. In the meantime he tries to reconnect with people he knows and to avoid the attention of several shady individuals that know him. That's the layout.
The mystery elements arise from the fact that he is rejected by a few, pursued by a duo of suspicious looking men, and approached by a bunch of unsavory roughnecks that know him well. Why the rejection? Why the persecution? What is the gang about? The film is parsimonious about handing out hints and clues that we need to answer those questions. The best we can do is work out hypotheses and see if they pan out at the end.
The core element of the mystery is revealed late in the film. Yet it did not completely resolve all the pending questions. Below is my guess on a few details that may help shed light on the plot. Sherlock should stop reading here.
The social context is important. Since the 90's, there has been a major influx of Albanians into Greece. In the film, the woman is Albanian. The man has a Greek name but is he really? The two pursuers are most likely Albanians. The gang is Greek. That's my allocation. Create your own. What I'm saying is that the Greek/Albanian divide needs to be considered seriously.