Isolde and Natasha bring Liliana and the crystal holding her spirit down to the ritual chamber beneath The Gnarly Tree, along with Olivia and Amelia. Natasha notes that she isn't entirely sure how to proceed, since she's never had to merge a spirit back with a body before.
Olivia draws a chalk door to summon Buffy, who is able to remove the sleepy spirit of Claire from Liliana, leaving the Eeee even more weak than she already seemed.
It's up to Olivia to keep Lili from collapsing while Natasha works a containment ward around them so that the released spirit doesn't try to escape. Once it's in place and the crystal broken, a smoky red version of Lili seems to form, and Amy suddenly has to struggle to keep herself from going demonic from the proximity effect.
The demon is eventually reabsorbed by Lili, who then bites Olivia and drinks some of her blood (or 'Skeek Juice' as Amy and Isolde call it).