Chiyo Takamura, a hardworking 30-year-old woman, is dedicated to her job in the civil engineering department of a major construction company. Her life takes an unexpected turn when she is confessed to by Ichika Seo, a charming 45-year-old man who holds the position of vice president in a foreign company. Despite being caught off guard by his sudden confession, Chiyo gives him a chance and agrees to a trial romance with him. As they explore their feelings for each other, Chiyo and Ichika navigate the challenges of their age difference and the expectations of society. Chiyo, who always sees Ichika as just a lunch buddy, starts to see him in a new light and realizes that there may be more to their relationship than she initially thought. Meanwhile, Ichika, who has been in love with Chiyo for some time, is determined to win her heart and prove that age is just a number. Chiyo and Ichika embark on a journey of self-discovery, learning about each other's past, dreams, and aspirations. Their romance is tested when encountering obstacles, including disapproving colleagues and conflicting work schedules. Despite these challenges, Chiyo and Ichika remain committed to each other and continue exploring their relationship's possibilities, hoping to find lasting love and happiness.