As someone who was born in Hong Kong and worked in Hong Kong for 7 years on and off (grew up somewhere else), it is extremely interesting to watch all the scenes shot on location.
However, I would say that the storyline is unrealistic as kidnappings rarely happen in Hong Kong, especially as recent as 2014. Furthermore, kidnappers know and understand that expats are relatively cash poor as compared to the successful local businessmen. Such privileged expat packages no longer exist in Hong Kong.
Having said that, I’m intrigued to continue watching as the story unfolds as it is rather entertaining.