The competition consisted of four rounds; the questions in the first three were chosen from hundreds that had been asked to the Think Tank beforehand, with all members answering individually.
For the fourth round, the host asked five pairs of questions that had not been put to the Think Tank, alternating between contestants; the one with the higher total decided who played first.
If the round ended in a tie, the host continued asking pairs of questions until one contestant answered correctly and the other missed.
The maximum potential winnings total was £2,600, obtained by answering every question correctly in the first three rounds and succeeding in the final.
In the first series, the members of the Think Tank were Lucy Barry, Max Bruges, Len Crumbie, Anisha Devadasan, Arminel Fennelly, Cleve Freckleton, Ken Fullicks, Tristan Harper, Diane Hill, Abi Kanthabalan, Jackie Waring and Peter Wong.
Jane Rackham said in Radio Times: "Turnbull is a charming host while there's a great deal of good-natured teasing and laughter between the Think Tank members".