Ambrosia Wellington receives in the mail an invitation to her 10-year reunion, along with an anonymous note that reads “We need to talk about what we did that night.” It seems that the secrets of Ambrosia’s past aren’t as buried as she’d believed. Amb can’t stop fixating on what she did or who she did it with: larger-than-life Sloane “Sully” Sullivan, her former best friend, who could make anyone do anything. At the reunion, Amb and Sully receive increasingly menacing messages, and it becomes clear that they’re being pursued by someone who wants more than just the truth of what happened that first semester. This person wants revenge for what they did and the damage they caused --- the extent of which Amb is only now fully understanding.