Episode 6 started with Alaric on the phone with Caroline, upset that she wouldn’t be there for the twins’ Sweet 16 birthday.
However, he said that’s what Caroline was really doing, she was out following a lead.
Later in the episode, the undead Jo asked Alaric if the girls knew what would happen when they turned 22, clearly referring to the Gemini Coven Merge for twins.
He added, “I can’t exactly tell them what you’re really involved in.”