Split "is a glimpse into the life of Casey, an outstanding pitcher. As her 30th birthday approaches, when she sees a strange and ominous statistic in a local newspaper, her life takes an unexpected turn. Her recently deceased father, a professional pitcher, has been absent for a long time and has a strange personality, leaving her not only a mother who eats and drinks for free sitting on the sofa, but also a lingering idea in her mind, which is to live up to her "; above average level"; According to standards, she only has less than a month to meet and marry the man she has always dreamed of. Despite her friends pleading with her, she still began planning a plan, but a fatal conflict on the local lane made her wonder what she really wanted - number 7... or number 10?