Gemma Doyle is looking forward to a holiday from Spence Academy—spending time with her friends in the city, attending balls in fancy gowns with plunging necklines, and dallying with the handsome Lord Denby. Yet amid these distractions, her visions intensify—visions of three girls dressed in white, to whom something horrific has happened that only the realms can explain. The lure is strong, and soon Gemma, Felicity, and Ann are turning flowers into butterflies in the enchanted world that Gemma takes them to. To the girls' great joy, their beloved Pippa is there as well, eager to complete their circle of friendship.

But all is not well in the realms—or out. Kartik is back, desperately insisting to Gemma that she must bind the magic, lest colossal disaster befall her. Gemma is willing to comply, for this would bring her face-to-face with her late mother's greatest friend, now Gemma's foe—Circe. Until Circe is destroyed, Gemma cannot live out her destiny. But finding Circe proves a most perilous task...

This sumptuous companion to A Great and Terrible Beauty teems with Victorian thrills and chills that play out against the rich backdrop of 1895 London, a place of shadows and light...where inside great beauty can lie a rebel angel.

潔瑪道爾滿心期待斯賓塞學苑放假，她要和好友們在倫敦好好玩一玩，穿著華麗的低胸禮服參加舞會，並與英俊瀟灑的丹比男爵譜出一場浪漫戀曲。但就在精彩的假期計畫中，潔瑪眼前的景象卻愈來愈清晰，她看見駭人的悲劇降臨在三名白衣女孩身上，而只有「幻境」才能解釋這一切。幻境魅惑的力量相當強大，很快地，潔瑪帶著菲莉希蒂以及安，三人進入了如夢似幻的魔力世界，繽紛花朵幻化成了栩栩如生的蝴蝶。令女孩們更開心的是，她們最喜歡的琵帕也在那裡，迫不及待加入她們的行列。

但「幻境」並非樣樣美好，現實世界亦然。卡提克回來了，他力勸潔瑪封印魔力，否則會大難臨頭。潔瑪何嘗不想，因為這股力量會引領她與媽媽生前摯友，如今卻是她的仇敵──瑟西──正面交鋒。不除掉瑟西，潔瑪就無法完成此生宿命，但想找出瑟西，過程卻險阻重重。

本書是小說《絕美魔力》同系列姊妹作，內容豐富精彩，以1895年維多利亞時期的倫敦為時代背景，華麗繽紛，懸疑驚悚，光明與黑暗並存，美麗外表下潛藏的，可能是叛逆天使。