A one-year age-gap couple, Hyun Jungwon and Joo Hosu. Each thinks the other has fallen into boredom, so they try to mend their relationship—but things only become more tangled. Then Jungwon comes across a rated-19 novel that claims to be the ultimate cure for relationship stagnation. When Hosu discovers it, their situation takes an unexpected turn… A chaotic first-night romance of a clueless, inexperienced couple!