This volume concludes the trilogy and is set a year after the previous one, when Gemma is about to come out to society. She's still at the Spence Academy, but finds she has lost her power to enter the realms at will. When she finally does get in she discovers the Pippa has been building a little queendom for herself and has changed significantly, now bordering on megalomaniacal evil. Pippa is unable to cross to the afterlife because she has become so embedded in the realms by this time.
Feeling like her life is slipping out of her control, Gemma decides she has no choice but to follow every clue and discover what is really going on here since her mother was so utterly useless in helping her. After rambling around London following rather tedious clues, Gemma enters the realms again and visits the Winterlands in hopes of finding the so-called Tree of All Souls. When they touch the tree they get visions, and Gemma's is of Eugenia Spence telling her about this mysterious girl in lavender she keeps seeing. Evidently, the girl has a dagger which is somehow a threat to the Winterlands.
Felicity and Ann are becoming increasingly frustrated with Gemma's refusal to allow them back into the realms, and they discover that they don't need her because there's an alternate way to get there. When Felicity encounters the very dangerous Pippa, the latter tries to talk her into eating the realm berries which will maker her visit to the realms permanent so she can always be with Pippa - who's true love was evidently Felicity all along.
In a big showdown at the end, Kartik sacrifices himself to save Gemma who then does what we all thought she'd done in volume two which was to give her power back to the realms, robbing herself of power and sealing the two worlds from each other. She then retreats to the Americas which is what all young girls do when they have no power, of course!
Some issues with this last volume, but overall, I recommend it as a fitting finale to the trilogy. It's a worthy read, despite a few problems here and there (mostly there).