Katherine fell in love with Stefan when she met him in Mystic Falls in 1864. Although she was also seeing Damon, she had a clear preference for Stefan. She secretly watched over him while running from Klaus. Katherine was unwilling to put her love for Stefan above her own survival and when she returned, they became enemies, as Katherine wanted to deliver Elena to Klaus in exchange for her freedom and Stefan was in a relationship with her at the time. Dead Man on Campus marked the formation of a positive relationship between Katherine and Stefan. Katherine helped Stefan deal with his traumatism from being locked away and repeatedly drowned to death by Silas for three months, and then he saved her from killing herself by catching her as she was about to hit the ground after jumping from the top of a clocktower. In The Cell, Stefan was still watching on Katherine so she did not commit suicide.Later, the two of them are locked together in a cell by Caroline as part of an experiment to try and help Stefan deal with his traumatism from being locked away. Katherine managed to make Stefan overcome the traumatism by telling him that the real problem wasn't how he felt about being trapped, but rather the pain he felt from Elena leaving him and being with his brother Damon. They almost kissed but before they can Caroline opened up the safe, worried because they had gone silent. Later, when Caroline wasn't watching them anymore, they kissed each other that progressed into sleeping together. And this episode was advertised by Nissan  LOVE YOU ALL STAY SAFE  follow us on instagram and twitter  @tvdaspodcast and email us at [email protected] --- Send in a voice message: https://anchor.fm/cee-jay3/message