where does the sea begin

The phrase "where does the sea begin" is associated mainly with a 2024 Japanese drama series titled "Where Does the Sea Begin" (Umi no Hajimari). This drama tells a story about family, parental love, and unexpected bonds. The story centers on a man named Natsu Tsukioka who discovers after his college girlfriend Mizuki Nagumo's funeral that he has a 7-year-old daughter he never knew about, named Umi. The series explores the themes of love, loss, and the beginnings of new family relationships. If the query is metaphorical or poetic, it was not directly answered in the search, but the title itself hints at the beginning of the sea representing the beginning of life or relationships, as depicted in the drama's story. Would a poetic or scientific explanation of where the sea begins be helpful as well? Or does this answer regarding the drama series satisfy the inquiry?