On the surface, Clara Barron seems to have it all: a job as an OB-GYN; a great house in LA; and a loving family. But, the one thing Clara doesnt have figured out is her love life. Pressured by a family wedding in Mexico, Clara asks a co-worker to pose as her boyfriend for the weekend festivities,- only to be caught by surprise when her ex- boyfriend (and family favorite) suddenly shows up after disappearing from her life pletely. Torn, Clara must decide between going back to the past or open her heart to new and unexpected possibilities.

就读于都立东京高中的水岛树权（斎藤工 饰）漂亮帅气，是无数女孩心仪的对象，连教务处长富良野健儿（津田寛治 饰）的女儿圭子（乙黒えり 饰）也对他青睐有加。恋人节当天，树权收到同班转校生有角藻奈美（川村ゆきえ 饰）的巧克力，可是这个味道有些奇异的巧克力让他的人生产生剧变。本来藻奈美是一个存活上百年的吸血鬼，她用掺有本身血液的巧克利巴树权酿成了一只吸血鬼。发现藻奈美真实身份的圭子想要搭救树权，成果却坠楼身亡。概况薄弱虚弱的健儿现实上是个疯狂的科学家，他将女儿的尸身革新成威力壮大的僵尸。一时候校园上空阴云密布，吸血少女和僵尸少女的战役就此拉开帷幕……本片按照内田春菊的漫画《『闇のまにまに～吸血少女対少女フランケン～》改编。