Erika lived a peaceful life as the young wife of a small construction company president. Since their school days, Yugo had harbored deep feelings for her. Due to his unstable personality, he rarely attended school and still couldn't let go of his obsession with Erika. Years passed after they both reached adulthood, and Yugo eventually got a job at Makoto's company. There, he unexpectedly reunited with Erika. Unable to suppress his long-held emotions, Yugo began openly expressing his feelings toward her. At the same time, consumed by jealousy over Erika's graceful lifestyle, Yugo started exhibiting increasingly disturbing behavior.