A photo of Herve and Dr. Lester that was shot by Harriet because she thought something looked off. The photo was torn during an argument between Harriet and Ryan. It is the memento used to get into Warcadia. Only one person can actually use the photo at the Henge, the other will be waiting at the Henge and both characters will jump together.
Ellen's half of the photo is obtained after talking to Harriet.
Keat's half of the photo is hidden in the Lighthouse Keeper's home.