Spoilers ahead for Episode 12 of Legacies Season 1, called "There's A World Where Your Dreams Came True."
Although a fair amount of Legacies so far has focused on Hope Mikaelson and the Monsters of the Week, the threat of what could be in store for Lizzie and Josie has loomed over everything. Tradition dictates that twins born into the Gemini Coven must undergo a deadly ceremony known as "The Merge." Alaric and the off-screen Caroline have been working to find a way around The Merge for their daughters, but "There's A World Where Your Dreams Came True" may have revealed that The Merge has to happen.
Here's how it all went down. In "There's A World Where Your Dreams Came True," Lizzie and Josie returned from their trip to Europe to see Caroline, who sadly remains off-screen and on her own adventures. Unfortunately, Alaric was busy with monsters and Hope drama, and he forgot that he needed to pick the girls up from the airport. Lizzie didn't react well to this news, which happened to coincide with the arrival of a Jinni, which is basically a genie who isn't bound to a rule of only three wishes.
Upset that Hope seemed to be getting all of Alaric's attention, Lizzie wished that Hope had never come to the school. When that backfired and the school was struggling without the big check Klaus has written Caroline when he knew Hope would come to the school, Lizzie tried to fix things... only for them to take a trip down to New Orleans, meet Hope, and invite her to the school. Time for wish #2!
For wish #2, Lizzie wished that there was never a Salvatore School at all. This reality was even worse, as the girls go to public school, where Alaric is the habitually day-drunk history teacher. Josie and Alaric were tasked with watching over Lizzie, and the super popular cheerleader version of Josie was sick of it. Lizzie then learned that Klaus lived and opened the Mikaelson Boarding School, bringing Hope into the picture again. Poor Lizzie. Wish #3 time!
For her third wish, Lizzie went hard and wished that Hope had never been born. Lizzie found herself in a post-apocalyptic world where supernatural beings are hunted. Lizzie returned to the Salvatore mansion, which was a shell of what it once. She discovered a vigil going on, and she learned an awful truth from Alaric: Josie is the one who died. The third wish version of Alaric finally told her the truth that real Alaric and Caroline have been hiding.
Alaric explained The Merge as the Gemini Coven tradition that requires twins to merge when they turn 22. It is a battle of wills, and only the "stronger" of the twins will survive, with the winner absorbing the power of the "weaker" twin. Caroline is on a mission to find a way to prevent The Merge so that one of her daughters never has to kill the other, but no luck.
In the third reality, Lizzie learned the truth, and she went dark and grew dangerously paranoid as a result. She began to see Josie as a threat, and lost control of herself, killing her sister. Lizzie was obviously distraught at the news, and she was desperate to get back to the reality where her sister wasn't dead. The Jinni eventually agreed to undo her previous wishes, but there was a catch: Lizzie would forget everything that went down in the false realities.
That meant that she would forget about The Merge, but the Jinni revealed that that a remnant of what went down would linger, and she would slowly go insane because of it. When that remnant eventually drives her to the point of finding out about The Merge, Lizzie will be dark and paranoid, and therefore in a place where she'd kill Josie all over again.
Does what happened to Lizzie mean that The Merge has to happen, or at least the results of The Merge will happen? Could this go down years before they turn 22? Can anything be done to stop one sister dying? Caroline hasn't been successful in finding a way around The Merge yet, and now a dangerous seed has been planted in Lizzie's mind.
A lot may depend on whether or not Alaric and Caroline come clean to their daughters about what's in store. They probably wouldn't take the news well no matter how the bombshell is dropped, but Lizzie could have a support system around her as she dealt with the news. The way things stand now, the odds are stacked against both twins surviving to their 23rd birthday. Hopefully this new development will somehow result in Caroline turning up!
Only time will tell. Lizzie's situation means that viewers won't have years until the twins turn 22 before they have to worry about the effects of The Merge, as she could snap sooner rather than later. Legacies was recently renewed for Season 2, so I would be shocked if the storyline doesn't continue beyond the first season. Tune in to The CW on Thursdays at 9 p.m. ET for new episodes of Legacies in the midseason lineup.