A fudanshi dies surrounded by BL manga and wakes up as the literal love interest in his own fantasy. The show knows exactly what it is: a four-minute victory lap for people who read this stuff because the genre speaks to them, not despite it. Nagi isn't a character who happens to want sex, he's a celestial being who needs Kotone specifically, which means the entire premise is built on the fantasy that your obsession could actually matter to someone.
Kotone dies surrounded by his beloved BL manga and wakes up in a celestial palace where a serpentine deity named Nagi claims him as his spiritual consort. There's just one problem: Nagi needs to consummate their bond to ascend to dragon godhood, and Kotone's encyclopedic knowledge of yaoi tropes tells him exactly which role he's expected to play. Armed with years of fandom expertise, Kotone hatches a desperate plan to avoid becoming the bottom while somehow preventing himself from falling in love with the increasingly persistent Nagi. What unfolds is a collision between a devoted fan's theoretical knowledge and the messy reality of actual romance, where every BL scenario Kotone thought he understood suddenly plays out in his own life. The comedy comes from watching someone who's read every trope imaginable try to outmaneuver the plot that's now written him in. It's a cheeky love story that knows exactly what it is and refuses to let either Kotone or Nagi off the hook.