Summer of 17

Summer is coming and Paula is on a bus bound for the beach. She''s sixteen years old and that''s the last place she wants to be. She doesn''t understand anything about the world, neither her classmates, nor her parents, who have just separated and have gone on vacation at the same time with their new partners, leading her to the beach with her grandparents, where she hadn''t been for years, When all she wants is to be locked in her room.
There she will be reunited with childhood friends, who have changed, like everything around them. It even seems that there are much less people of her remembered it. Although everyone agrees that this is not normal.
What is happening at the beach?