Relationships are built on trust

Clarke and Lexa were the dream couple that everyone dreamed of being falling madly in love in their junior year of high school, only to have it crushed at a senior party a year later. When Clarke goes to get a beer and is gone for less then 5 minutes and come back only to find her girlfriend with her hand down her ex girlfriend Costia Greene's pants, running and breaking up with Lexa moving to San Francisco leaving behind a very sad and confused Lexa thinking the night of the party it was Clarke's pants her hand was down. Only to meet again when Lexa moves to San Francisco for a new job meeting her long lost love Clarke in a bar. After talking and fighting and yelling Lexa finally admits what she thought happened that night changing Clarke's mind completely on what happened. Once they happily get back together for a little over 4 months Octavia sent out a mass text telling everyone there was a high school reunion that everyone was going to that they descided it would be good to go and catch up with old friends....only to find one person neither wanted to see again. Costia.Greene.