My Mother, the Spy -Part 3 of the series

A stranger wearing an unusual pair of glasses that come apart at the bridge of the nose is on the island, and he has been asking around to find out if two English woman are living there.
Who is this person and does he pose a threat to Roulla and Sofia's safety?
Later, shots ring out and everyone ducks for cover.
See a short video at: https://stupeflix.com?v?Bhi7bmDSj/?autoplay=1
When Nico tells Sofia and her mother about this and also describes the man as well as his glasses, her mother gets a certain smile on her face and says she thinks it is Harry. She says he has probably come to warn them that an old threat from her days as a spy has reemerged and that Nico needs to find the man again. So is the man Harry and what does he want with Sofia and Roulla?