A lovey-dovey couple becomes a married couple overnight!? "Scarlet Night" is a secret organization that undertakes national missions. Juntaro and Iris, who are known as the strongest in the organization, are always fighting whenever they meet. In fact, these two are in a relationship of unrequited love. They don't want to admit that they are attracted to each other. But one day, they are ordered to pretend to be a married couple for a mission to protect the princess...!? What will they do? What will the mission be? The most difficult mission begins now!