Princess Principal/Recap/S2/E01 Chapter 1

Quoting from Wikipedia: "In response to the assassination attempt on the Queen, the Duke of Normandy begins cracking down on suspected Commonwealth of Albion spies. Concerned that their mole within the royal family may be a double agent, Control tasks the Team White Pigeon with making contact with the mole and investigating him. Ange disguises herself as Princess Charlotte and meets the mole in the royal palace, and is surprised to discover that the mole is Winston, the grand chamberlain and the man that used to take care of her when she was a child. Winston recognizes Ange and lets her know that he is aware she is the real Charlotte and the other is an impostor. Ange and Charlotte explain to the rest of the team that he knows they are investigating him. Despite knowing the risk of Winston exposing them, the team continues to investigate him and discovers that Winston has been secretly communicating with an unknown third party through coded messages he has hidden in the Queen's speeches. The team manages to expose him by feeding him false information and tricking him into sending out a message they can intercept. Control orders the team to detain Winston for interrogation, but Ange secretly arranges for his escape in return for keeping her and Charlotte's secret. Winston parts amicably with Ange but is shot by an assassin. With his dying words, Winston warns Ange that if she continues living a life of lies, she will end up like him. In the aftermath, both the Duke of Normandy and Control become aware of the unknown third party's involvement as the team feels defeated in failing to save Winston."


 * Chess Motifs: Sprinkled through the movie, starting with the codename of the double agent, "Bishop".  There is also a revealing chess game between the double agent and Ange.