My track record with J-Drama's been pretty productive lately & this one is another winner. More sombre & reflective than the Otaku-centric shows I've been enjoying, the salient feature here is the cross-cultural angle which I've not encountered before. As in, a 30-ish single Japanese woman ( Kana Kurashina ) who works in the lingerie section of a large store meets a younger Korean man ( Kim Jong In ) & a relationship ensues. The two countries have obviously had a long & usually tragic history & recent trade-war spatting is no surprise. On the other hand, Japan's long been a major K-Pop market & some group members are Japanese, so I think they're really stuck with each other ( plus very close geographically ). What gives this well-written show extra depth is the attention given by the script to the supporting characters & the consequent portrayal of modern life rings very true. The two leads are charismatic & premium eye-candy, though the lovely KK as a wallflower bereft of male interest is a bit of a stretch. The ending was also unexpected ( a good thing ) & it does suit the bigger picture. Whether you like it or not is up to you.
PS - the poster baffles me ! Since the story is a definite two-hander, why on earth would you have only one of the actors as the dominant picture ? A deliberate concession to Korea perhaps ?