The Best Parallel World Drama

The ending is a left open ended on purpose, but this drama keeps you on the edge of your seat the entire show.

You're not left wondering about loose ends as it's one of the few korean dramas that ends well and has good pacing.

While it's not explained why he is able to travel between the two worlds, you're not really left wondering why either he is able to due to the way it ends either.

Rain acting here is stunning as well. The only frustrating thing perhaps, is as the FMC which is more of a trope and not really a flaw. As there needs to be a hot headed policewoman who ignores police protocol and dives headfirst into danger without a partner backing her up.