One to Win was somewhat of a revival of Bob's Full House, which used the format of Bingo.
Each contestant was equipped with a Bingo Card with 15 numbers on them. Player #1's card had numbers 1-15, player #2's card had numbers 16-30, player #3's card had numbers 31-45. Their job was to fill-up their Bingo Card by answering general knowledge questions. Their cards were displayed on their monitors in front of them.
In round one, the players competed to cover all four corners of their cards by answering questions correctly. The first player to buzz in had a chance to answer. A correct answer covered a corner number on the card, but an incorrect answer locked that player out of the next question. The first player to cover all four corner numbers won a prize.
The object of this round was to complete the entire center line by answering questions from four different categories; each category had four questions. One player would choose a category, then a question from that category was asked. For each correct answer given, the player who gave the correct answer controlled the category board by choosing another category. The first player to complete his/her center line won a prize.
In the third & final round, all three players competed to fill-up their entire card (mark off the rest of the numbers). Before that round started, each player was given a Wild Card, which was a single card marked with a "W". At any point during the rest of the game, one player can use his/her Wild Card to stop another player's progress. As soon as the card was played, the player whose been hit with a Wild Card had a "W" marked in front of his/her podium in place of his/her Bingo Card. To remove the Wild Card, that player must answer one question correctly, though there was a 1/2 second delay in buzzing in. The first player to fill-up his/her Bingo Card wins the game an additional prize, plus a chance to win a holiday.
The winning contestant faced a 16 numbered square game board. Behind eight of those numbers were letters in a keyword. The other eight hid money amounts from £15 to £50. Should the player win the game without using the Wild Card, he/she chose which number to reveal for free. Now the player had 60 seconds to answer up to 16 questions. Each time a correct answer was given, the clock stopped and the winning player got to choose a number. If a letter was revealed, that player was one step closer to the holiday, but if an amount was revealed, s/he got that money amount. An incorrect answer or a pass kept the clock going. If the winning player can uncover all the letters in the keyword before time ran out or all the questions were asked whichever came first, s/he won the holiday. Either way, the winning player kept the combined total of all the amounts revealed.