This drama is amazing and I am so glad I stumbled across it, however - I think this is the type of drama you can only truly enjoy if you forget everything you read/saw about it. Neither the trailer, the Synopsis nor the original novel are an accurate portrayal of what the drama actually is like. I think a lot of people got mislead and then were disappointed.
SO, if you want to to watch it forget whatever you know about it.

I would say it's a story about an unlikely romance. Surprisingly flirty, touching and hopeful. What did Rihanna say? - We found love were it wasn't supposed to be. That's exactly it.
We have a strong, mature and hard-working FL in her 30s that has a high ranking job and doesn't loose her cool. On the other side we have a flirty, but beat-down-by-life car technician in his 20s.
The romance in this drama is very mature and raw - in the best way possible. Somehow it feels like censorship forgot to check this drama? - lol, not that I am complaining tho :D

Now about the mystery, murder, etc. - I have to give a disclaimer I don't watch a lot of dramas in that genre, which is why I appreciate the short length. I couldn't watch 20-30 episodes of a family fighting for inheritance.
Most of the mystery and murder happens in the final 3 episodes and during that time it's exactly like in the trailer, before that it's a slow but steady fight for inheritance among the Gao Family and seemingly undisturbed the ML and FL are getting to know each other, far away from the company. Which is the part I loved the most.

All in all this drama is different from what I watched before and I am glad I did.
+ the orchestral BGM also added A LOT to it feeling unique and intriguing