This was occasionally cute and I really found the twist unexpected. It's similar to The Call from last year, where a ruthless female killer travels through time. It was fun seeing the mystery unraveled, but I just didn't find the story all that compelling. Yeri approached this with her usual enthusiasm, and so much of her irresistible charm made this watchable. I'm sorry to say that Hongseok just couldn't match her energy. There was very little variation in his facial expressions. Ha Rin and Seo Jun's romance wasn't nearly as interesting or fun as Su Jin and Ui Yeong's. And I think Hye Min's storyline was so mishandled. Anticipating a drama with a bit more teeth for Yeri in the future.