In Yokujou Climax, high school student Mio Omori faces the challenges of her impoverished family life. Juggling part-time work to help her ailing mother and younger brother, Hinata, Mio's world is turned upside down when brash Shohei Jinnai buys her first kiss. Their tumultuous relationship unfolds a mix of love and animosity, leading Mio to discover unexpected depths in Shohei and in herself, offering fresh perspectives on life and human connections.