The Vampire Diaries is a story about Elena, a doppelganger who looks like Katherine Pierce, the love interest of Salvatore brothers Stefan and Damon. Elena is grieving the death of her parents and feels like she will never be happy again.
Then, a new student named Stefan Salvatore arrives and he and Elena fall in love instantly, despite her lack of knowledge about his past. Stefan's older brother Damon also shows up, intending to make Stefan miserable but ends up falling for Elena as well.
On her birthday, Damon gives Elena a cherished necklace, which makes her realize she loves him. In season 4, Elena and Stefan break up and she spends the following seasons with Damon, who makes her happy and helps her believe in herself.
Damon challenges Elena to be her best self and distracts her from the dangers around them. Luckily, Elena's own powers are awakening, along with those of her friends who have gifts to protect her.