Explain the of Esther's linking spell in the following episodes
The invitation was simple, yet it held the weight of a thousand years: a formal ball hosted by the newly reunited Mikaelson family. Elena Gilbert arrived on the arms of both Salvatore brothers, her presence a necessary piece in a game she didn't yet fully understand. The Secret Alliance [S3E14] Dangerous Liaisons
"The Vampire Diaries" Dangerous Liaisons (TV Episode 2012) - IMDb Explain the of Esther's linking spell in the
Summarize the that led to this reunion