The story begins with the following incident: Watsuji Mako kills her grandfather, Watsuji Yohei at his birthday party held at their family villa. Believing it to be self-defence, Mako's mother asks the gathered family members to help conceal the crime. Yohei's younger brother Shigeru and his chief physician Mazaki try to stage the killing as a robbery gone wrong. Mako's friend Harumi, who was also a guest at the party, becomes an unwilling accomplice. They try to disrupt the police investigation without knowing there is a traitor in their midst. Soon, the truth with be revealed... (Source: translated from ORICON NEWS)