Ryouhei Arisu, a 26-year-old school counselor happily married to Yuzuha Usagi, faces a dramatic shift when he learns about his wife's impending childbirth. Rushing back to Tokyo to be by her side, his world is upended by a sudden storm that leads to a fatal accident. Instead of death, Arisu finds himself in Borderland, a mysterious realm where survival hinges on winning macabre games. Determined to escape this perilous land and reunite with his loved ones, Arisu unravels the sinister rules governing his fate, realizing that his journey home may demand more than mere luck.