Fel fampirod i gyd, mae Kat Finn a’i Mam yn yfed Hema, amnewidyn gwaed synthetig, i oroesi yng nghanol pobl. Nid yw Kat yn edrych ymlaen i fywyd anfarwol o grafu heibio, ond wedyn mae’n cael ei derbyn i Ysgol Harcote, ysgol i fampirod.

Tyfodd Taylor Sanger lan yn y byd fampirod cyfoethog, ond mae hi’n flinedig o’i gwerthoedd ceidwadol, yn endwedig o ran rhywioldeb, gan ei fod mas a’n browd o fod yn lesbiaidd. Ond mae wedi dychryn pan mae hi’n dysgu Kat Finn yw ei hystafellydd newydd, achos roedden nhw’n ffrindiau gorau unwaith.

Pan mae Taylor yn cael gafael am corff marw fampir, a Kat yn gwneud darganfyddiad yn archifau’r ysgol, mae’r ddwy yn sylweddoli bod yna gyfrinachau yn Harcote – cyfrinachau sy’n ymwneud a’r ffigurau mwyaf pwerus yn y byd vampirod, a’r gwaed synthetic maen nhw’n dibynnu arno.

Kat Finn and her mother can barely make ends meet living among humans. Like all vampires, they must drink Hema, an expensive synthetic blood substitute, to survive, as nearly all of humanity has been infected by a virus that’s fatal to vampires.

Kat isn’t looking forward to an immortal life of barely scraping by, but when she learns she’s been accepted to the Harcote School, a prestigious prep school that’s secretly vampires-only, she knows her fortune is about to change.

Taylor Sanger has grown up in the wealthy vampire world, but she’s tired of its backward, conservative values–especially when it comes to sexuality, since she’s an out-and-proud lesbian. She only has to suffer through a two more years of Harcote before she’s free. But when she discovers her new roommate is Kat Finn, she’s horrified. Because she and Kat used to be best friends, a long time ago, and it didn’t end well.

When Taylor stumbles upon the dead body of a vampire, and Kat makes a shocking discovery in the school’s archives, the two realize that there are deep secrets at Harcote–secrets that link them to the most powerful figures in Vampirdom and to the synthetic blood they all rely on.