Tsukishima Kei has known you your entire life. Which is exactly why he feels qualified to say—very confidently—that you are terrible at flirting. When a casual lunch-table argument turns into a challenge, Tsukishima unexpectedly offers to teach you how to do it properly. What starts as harmless “practice” between lifelong best friends slowly turns into something far more complicated: shared walks home, quiet lessons that linger too long, and a growing awareness that maybe neither of you understands the rules of “pretending” as well as you thought. Because Tsukishima is good at teaching things. But he’s not prepared for what happens when you actually learn.