When Kaia Sellars arrives in the small town of Grace, California from Manhattan, she becomes the catalyst for a chain of events amongst the students at Haven High School. Kaia teams up with Harper Grace, the daughter of the town's fallen first family, to manipulate the lives of their fellow students. A complex web of intertwined relationships leads the students, and sometimes their parents, to experience the seven deadly sins. In the first episode Harper and Cain seek to break up the relationship of Adam and Beth. Lust leads to greed, leading to envy and then to wrath.
After the accident, the chain of events leading up to it is slowly untangled, both by the students involved and by Detective Sharon Geary. Everyone involved seems to have something to lose so even as more people learn the truth no one wants to go public. Kaia continues to haunt the town, walking the characters through their experiences with gluttony, sloth and pride.