This drama seriously made me cry. You need guts to watch this drama . Hey ja's Alzheimer's disease and Joon Ha's death all is just heart wrenching .
In the starting 4-5 episode , while Hey Ja was still young, that actually showed how she met Joon Ha in her time and chat with her two friends (in 1970).Then she saw her son(whom she thought as her father) getting into a accident , she saved him but for her in that accident he lost his leg, this was actually her hallucination of her son's accident which happened while he was little.
And about Joon Ha's kidnap for insurance money and got beaten up there and her saving him , this was Hey ja's hallucination of the real Joon Ha whom she could not save actually in that time . Her mind repeated all those moments which she spent with Joon Ha like stoping him from hitting himself, etc, etc.
Even though I was confused after tenth episode and in the beginning of 11th episode but seriously 11th and 12th episode are really the main table turners . The last episode made me cry because of all the emotions mended up in it .
Tough the watch played a specific role in the whole drama but still it was not a time machine . It was just a way through which Hey ja kept having those hallucinations.