A pair of contestants are given a chance to win up to £100,000 by answering a series of multiple-choice questions in two rounds.
All questions require the contestants to select the answer that falls either first or last in a particular sequence (e.g. the first actor to portray a comic book villain in a movie, or the bingo call that corresponds to the lowest number).
The second round consists of five questions, in which the contestants attempt to select the correct answer.
Once a question has been asked, the remaining envelopes are secretly assigned in reverse order compared to the first round, so that the correct answer is paired with the lowest value still in play.
These amounts are displayed on an onstage video wall, allowing the contestants to keep track of which ones are still in play.