|“|| Caroline: What if she can't forgive me?|
Stefan: She doesn't think there is anything to forgive. She just wants you to be with her.
— Stefan telling Caroline to spend time with her mom before she dies.
THE MERGE — When Liv and Luke’s father arrives to town to celebrate their birthday, they try and convince him to let Jo and Kai take their place in the merge ceremony. After Tyler finds out that the merge is happening sooner than he expected, he urges Liv to let him talk to her father. Meanwhile, after Caroline’s plan to cure her mother takes an unexpected and devastating turn, Elena, Stefan and Damon gather at the hospital, while Jo attempts to save Sheriff Forbes’ life. Lastly, with the merge set to take place, Damon’s risky plan quickly sends things spiraling out of control, forcing one of the twins to take matters into their own hands.
- Antagonist: Kai.
- Elena has a new daylight ring made by Jo.
- Caroline learns that her mother Liz had signed over the deed to their house, which explained how Colin could enter the Forbes House without being invited inside by Liz herself.
- Colin Phelps arrives in Mystic Falls after dying with Caroline's blood in his system. It was then revealed that vampire blood does not actually cure cancer, but instead accelerates the cancer cells' rate of production. As a result, Colin's brain tumor grew to what Jo described as "Stage 10 cancer," which does not actually exist. Colin's accelerated cancer caused him so much pain that he begged Caroline to kill him after trying and failing to kill himself, and Damon ultimately ripped out his heart as a mercy killing.
- Jo tries to help Sheriff Forbes by giving her transfusion of human blood in order to stop the vampire blood in her system from causing the same effect on her as it did on Colin Phelps, but it doesn't work.
- Damon frees Kai after catching Tyler attempting to do it. Because all of the Traveler magic Kai absorbed had faded away, he was unable to use it to hurt Damon, Damon was able to make a deal with him-- Kai could siphon the magic that makes up vampire blood from Liz's system to save her life, and in return, he can use the magic he took in the merge ceremony against Jo like he intended all along, as there was a Mercury-Venus conjunction overhead.
- The fact that Kai siphoned the vampire blood/magic from Liz's system implies that Kai or another Siphoner could use their power to kill a vampire by siphoning the magic of their vampirism, much like the effect of the Magic Purification Spell.
- Elena threatens to rip off Kai's head if he doesn't get to siphoning off the magic in the vampire blood in Liz's body, and Kai jokes that she and Damon put the "fun" in "dysfunctional."
- Elena tries using CPR on Liz after her stops and Kai has siphoned off the magic of the vampire in her system.
- All the magic that Kai absorbed from the Travelers' spell has gone away while he's been asleep, this is seen when he tries to inflict pain on Damon.
- It's revealed by Joshua Parker that if the twins of the Parker bloodline don't perform the Merge before he dies, the Gemini bloodline will end, as the lives of all of the members of the coven are linked to their leader. He also mentions that the the traits of the weaker twin that dies in the Merge will be absorbed by the one who survives, that the souls of both siblings will unite into one new being.
- Joshua Parker tries to force Liv and Luke to merge to stop Kai, but he is stopped by Tyler, who knocks him out.
- Despite the fact that she is not strong enough to fight him off, Jo accepts to merge with Kai, refusing to run from him anymore.
- Luke intervenes in the Merge between Kai and Jo, and offers to merge with Kai instead. Due to the fact that his imprisonment had kept Kai at the age of 22 and that they were of the same bloodline, it provided the needed loophole to allow them to attempt the Merge.
- However, Luke dies during the Merge, and Kai absorbed his ability to possess magic, along with several of his personality traits.
- Damon tried to take Elena on a date that they have already have been on before during the "summer of their lives," which was first taking her to dinner and then to a theater where French films are playing and sit in the back of the theater and throw popcorn at the hipsters.
- Elena and Damon share their first kiss since Home.
- Originally Elena wanted to start over with Damon; however, after witnessing the near death of Sheriff Forbes, she chooses to resume where they left off, realizing that life is too short even if you are immortal.
- Elena doesn't speak French, even though she was taking French during her Sophomore year at Mystic Falls High School which is a class she took with Stefan as well as established in the Pilot.
- In real life Nina Dobrev speaks French as well as Bulgarian, making her trilingual.
- Joshua Parker was last seen in Fade Into You.
- This is the last appearance of Lucas Parker in the series, as he's killed in The Merge with Malachai Parker.
- Damon is the second vampire in the TVD series to have their neck magically snapped. The first was Elena in Woke Up With a Monster and by the same person, Kai.
- Elena is the first vampire to have two different witches make a daylight for her in either series.
- This is the first episode to feature Jo, but not Alaric.
- Colin Phelps is the second vampire unintentionally created with Caroline's blood that is killed.
- This is the fourth episode in the series to feature a birthday. In this episode, it's Luke and Liv's 22nd birthday.
- Mystic Falls, Virginia
- McKinley, Virginia
- Colin Phelps - heart extraction, killed by Damon Salvatore.
- Lucas Parker - died due to being the weaker twin in the Merge, killed by Malachai Parker.
Behind the Scenes
- This episode had about 1.47 million viewers in the USA.
- Hashtag during the airing is #TwinMerge
- "Prayer For The Dying" is a song by Seal from his self-titled studio album released in May 1994.
- "Hipsters" are a subculture of millenials living in urban areas.
- "Witch doctors" were originally a type of healer who treated ailments believed to be caused by witchcraft.
- Elena to Damon: "If we're gonna do this, we can't just pick up where we left off."
- Stefan: "The blood didn't heal him. It sped up his cancer and killed him."
- Sheriff Forbes: "The same thing is going to happen to me."
- Caroline: "Why did I feed her that blood?"
- Stefan: "You took a risk. You did it out of love."
- Elena to Damon: "Life's too short. I don't want to waste another minute."