Roommate

Harumi Hagio (Keiko Kitagawa) is injured in a traffic accident and  spend some time in hospitalized. There she comes under the care of a kind and supportive nurse, Reiko Nishimura (Kyoko Fukada). They soon discover an affinity for each other, and when Harumi leaves the hospital, Reiko suggests that they share an apartment and the two move in together. In addition to taking very good care of Harumi, Reiko offers to also take over negotiations with Kensuke Kudo (Kengo Kora), the driver who caused the accident, and his insurance-agent friend Shinichi Hasegawa (Hiroyuki Onoue). Harumi becomes completely dependent upon Reiko. Their life together is going very well, until Reiko begins acting strangely. Harumi's initial bafflement changes gradually to fear. One incomprehensible event leads to another, and suddenly Harumi is embroiled in a murder. Now she realizes there is a third person in their relationship: Mari. But where did Mari come from? As Mari becomes more and more violent, Harumi descends into a state of terror at what is happening around her. The truth, when it is revealed, is so astonishing she could never have imagined it.