The overall story, once it gets interesting, is good,
Gong Yoo and the female lead are excellent. Worth watching? Yes! ... once

First, "The Trunk" is a red herring. It has little actual relevance to the plot.
It's supposed to be so valuable - worth billions, yet every main character seems to have one.

Best scene - the fake wife thumping the real wife. Full marks for satisfaction!!
Worth watching just for this.

Finally, while the story was unique and well thought out, the amount of effort put into the ending was very disappointing ... AFTER EVERYTHING THEY GO THROUGH ... the writers give us a vague ending?
I'm sorry, but it wasn't cute, and it didn't cut it. Very underwhelming ending. Thoroughly lame.