While Maxwell Smart and the Chief are playing chess in the Regency Club, a waiter makes an assassination attempt of the chief by poisoning the chief's coffee. The manager of the club, Cedric Devonshire, stops the chief from drinking the acid-filled coffee, but not before the KAOS waiter escapes. While Max, the Chief, and Agent 99 are discussing the best plan of action, a secret meeting is being held at KAOS headquarters. It turns out that Mr. Devonshire runs the local KAOS branch, as he is yelling at the waiter for being so careless in the assassination attempt. He then orders his men to abduct Agent 86. They succeed and keep Max locked up in a prison cell. Here, Devonshire administers a brainwashing pill to Smart, effectively hypnotizing him. He gives Max orders to kill whoever says the word 'checkmate', which will be the Chief at their next chess game that evening.
In order for Devonshire's plan to work, Max needs to believe that he escaped on his own, so he has several of the KAOS agents leave Max ways to escape. Max either misinterprets the intentions of the KAOS agents or is completely oblivious to his chance of escape but eventually escapes in time for the chess match with the Chief. Max, having realized he's been beaten at chess too many times has purchased a "How to Play Chess in Six Easy Lessons" guide book. Devonshire watches Max and the Chief play, hoping the game will finish quickly because the brainwashing pill wears off at midnight, but gets increaingly nervous as Max keeps taking too long to make his moves. Eventually, Max makes a move he's sure will land him in victory but the Chief wins anyway However, before he Chief says 'checkmate', Devonshire says the word for him out of excitement. Agent 86 proceeds to shoot Devonshire. The Chief is shocked, but Max doesn't understand why he did it.
Back at the Chief's office, Max tells the Chief about the brainwashing and the Chief apologizes for doubting Max's story. Max says it's alright and suggests unwinding with Chinese Checkers. The Chief is pleased to play a game that doesn't use the word, "Checkmate". Max then takes his gun and is about to shoot the Chief, who quickly ducks under his desk. Max apologizes, stating that it's hard to break a bad habit.
- Devonshire - Murray Matheson
- KAOS Agent - Tony Lo Bianco
- KAOS Agent - Ken Scott
- Woman Agent (Shirley) - Eileen O'Neill
- New Control HQ number: 555-6213