THE 100th EPISODE: FLASHBACKS TO KATHERINE’S EARLY LIFE — As she faces a new crisis, Katherine remembers the traumatic night in 1490 when she gave birth to the daughter who was immediately taken from her. Stefan lets Elena, Caroline and Bonnie know that Katherine’s health has taken a turn for the worse, while Damon, Matt and Jeremy discuss some of Katherine’s most notorious moments. Nadia (guest star Olga Fonda) comes up with a frightening plan to protect her mother, and Stefan and Elena are forced to help her. Meanwhile, Caroline is mortified when she realizes she forgot to fill Elena in on the latest shocking gossip, then indulges in a little scandalous behavior of her own. Finally, Elena and Katherine share an unexpected moment of connection. Chris Grismer directed the episode written by Julie Plec & Caroline Dries.