Namely, why Alison moved away.

It's been almost two years since Pretty Little Liars came to an end, and all the Liars seemed to get the happily ever after they had been looking for.For Emily and Alison, this meant finally getting for a life together and with their twin girls. But when Sasha Pieterse was announced to be joining the Pretty Little Liars spin-off as Alison, eagle-eyed fans began to wonder happened to the couple - especially since it didn't appear as if Emily would be making the move to Beacon Heights with her. Pretty Little Liars: The Perfectionists officially premiered in North America on Wednesday night - angering the question of what happened to the fan favourite couple. Spoilers for Pretty Little Liars; The Perfectionists are below this point.  It looks like Emison didn't quite get the happily ever after fans thought they did, though, as the spin-off picked up with Alison's move to the Pacific Northwest. After Ali moved into her new house, she caught up with Mona, who, in another nod to the OG series, admitted the reason she moved to Paris (to keep the Drakes in her a dollhouse prison) had "gotten away from her". "Emily loves me. She just can't get past the past," Ali said, as she spoke about her relationship with Emily and why she had made the move solo. And when Mona told her she thought the pair had been happy, Ali added: "We are. And then we're not. It always comes back to trust." Perfectionists showrunner Marlene King told TV Line that they were going to "explore" what had happened with Ali and Emily's relationship. She said:

“When we left them, they were so happy. What would truly break them apart? When we looked back at the show, the one thing they always bumped up against was trust.”