An individual contestant, or a team of two or three people, attempts to unlock a safe containing a cash prize by answering a series of questions that steadily increase in difficulty.

The cash prize begins at £3,000 after it is won and increases by £500 per game in which it goes unclaimed.

The prize is locked in the safe and secured with a random combination code of three unique digits.

The game proceeds through three stages of increasingly difficult general knowledge questions, requiring the team to select one correct answer from a set of three.

As of series 2, Brewis offers "Lesley points" to Allwright or the team for supplying additional facts or trivia about the questions in play.