"Saving money is the best entertainment and the perfect way to kill time." So said Yui Katakura, a 40-year-old single woman. She has deliberately avoided anything she deems to be uneconomical, including romance, marriage and childbirth. During a free medical examination, she is diagnosed with cancer and told she only has a year left to live. Although the doctor urges surgery, Yui secretly feels relief. "If I'm going to die, there's no need to save money anymore." Her life shifts when Sena, a pink-haired nightclub host down on his luck, unexpectedly approaches asking "Can you lend me some money?" Yui responds by "buying" him for 720,000 yen. What begins as an odd arrangement gradually becomes a warm, unconventional bond, and to their surprise, an unpredictable love gradually starts to take shape between.