This is a very modern alien version of Romeo and Juliet, a famous tragedy by Shakespeare of a forbidden love, but also a story of friendship and coexistence between two different cultures - human and alien - just like a real world's culture clash.
The trivia item below may give away important plot points.
This is Grey Damon's third time his character gets killed off, two being in the final episode and one being prior to. The Nine Lives of Chloe King (2011) is the other show where he dies in the final episode, and The Secret Circle (2011) is the one where he dies prior to. Each TV series only lasted one season.