Shin Hae-In's character balances the quiet, vulnerable persona of a stressed musician with a striking, charismatic presence during her late-night commutes. By day, Hae-in is the frontwoman and voice of the indie band "Long Afternoon," but she conceals her true fame in everyday life. Despite her underground success, she often wrestles with imposter syndrome, anxiety, and the exhausting pace of her artistic pursuits despite being really attractive. Hae-in often relies on deflection—sometimes adopting an "offense is the best defense" mindset—not out of manipulation, but out of fear of losing the connections she treasures. They frequently run into each other on the late-night train and bond over their shared love for an indie musician named "Long Afternoon". While Yeon-woo is a dedicated fan of "Long Afternoon," Hae-in is actually the voice and creator behind the music—a fact she desperately tries to keep hidden from him despite him being her boyfriend.