Stranger 2 is the sequel to Stranger.
People might prefer to watch Stranger first before watching Stranger 2 as it is a continuation of the same story with the same characters.

Might I suggest that a requirement of 100 characters for something like this is really too much, I mean what am I supposed to write? Stranger 2 is the sequel to Stranger I think this is abundantly self-explanatory.

Modern day woman travels back in time after an accident and finds herself living in another era and becomes entangled in politics and falls in love.

male lead gets into relationship with female lead for revenge but ends up falling in love with her.
male lead is abusive
male lead and female lead's fathers were in business together, one betrays the other.

They're both based on books written by Gu Man.
Boss and Me is based on the book Come and Eat Shan Shan written by Gu Man;
You Are My Sunshine is based on the book Silent Separation written by Gu Man.