Eve goes on a mission to take on the mysterious force she saw in the mirror and finds herself in unfamiliar territory. When the gang discovers what she has done, Nick finds a way to join her. Meanwhile, an uneasy alliance is established when Capt. Renard is brought in to help and discovers this all may be connected to the person he cares for the most, Diana.
In order to get Mary to agree to a marriage, Lord Darnley must demonstrate his loyalty when she voices her concerns about his true intentions. Catherine and Narcisse work to repair King Charles' reputation after rumors spread about his strange behavior and threaten the throne.
When a mysterious woman finds her way into the vault, the team struggles to understand who she is and with whom her allegiances lie. Meanwhile, Alex must come to terms with her complicated feelings when she finds herself in a tight spot. Can Team Witness handle what might be revealed?