The 10th annual free winter film series at Guild Hall, presented in partnership with the East Hampton Library, kicks off Sunday at 4:30 p.m. with “A Bottle in the Gaza Sea,” the story of a 17-year-old French girl who emigrates to Israel with her family. Distressed by the hatred between Israelis and Palestinians, she writes a letter expressing her feelings and puts it into a bottle that her brother throws into the sea near Gaza. A few weeks later, she receives an email from a young Palestinian boy, and a long-distance friendship develops.