This drama really gets your brain thinking. It gets you thinking overtime trying to figure out whats going on. But its a great drama. The acting was amazing and the story line was great too. I think the leads had good chemistry and worked well together. It was all going well until it almost came to the end of the drama. Now if your scrolling through the comments trying to find opinions and possible answers to the ending i have my opinion. Since Han Tae Sul killed himself the war ended. No more nuclear bombing= no one died. Since this happened Seo Hae never had to loose her mother. Never had to live in the bunker. And never had to grow up in a nuclear waste land. Which then leads to the point where she never went to the uploader to save Han Tae Sul and stop the war. And never fell in love with Han Tae Sul. Which is why she disappeared. Han Tae Sul ends up back at the very beginning on episode 1 on the plane, (I don't quite understand why he remembers.) But with all his memories intact from the previous timeline i think he starts to hallucinate Seo Hae since he doesn't want to come to the conclusion she no longer exists (at least that version of her). The younger version of Seo Hae still exists but this is a child version of her that never gets to experience the nuclear war that kills almost everyone including her mother. Obvious;y you dont have to take my word on it afterall its my opinion and im not forcing it on anyone. But overall the drama was okay. I don'y exactly regret watching it but i only gave it a rewatch value of 6 because i hate sad endings. And i'm likely not to return to a drama that makes me bawl my eyes out at the end lol.