在莎拉（Sarah）生日那天，她最好的朋友维多利亚（Victoria）给了她一套基因检测试剂盒作为礼物，以便她可以更多地了解家人的血统。但是那天晚上，维多利亚被惨死了。几周后，莎拉敲了敲门，是警察。On Sarah's birthday, her best friend Victoria gives her a genetic testing kit as a gift so she can learn more about her family's lineage. But that night, Victoria is tragically killed. Weeks later, Sarah gets a knock on her door, and it's the police. As their homicide case ran cold, they decided to run the killer's DNA through the genetic testing site's database and there was a match: Sarah.