You have to crack the safe codes by throwing dice to earn victory points. Each safe card is worth 2 through 5 points. The player with the most points at the end of the game wins.
When it is your turn you throw all 5 dice. You have to put at least one dice aside. The pips of this dice tell you on which number you can put a marker on one of the three revealed safe cards.
Now you have to decide to stop or go on. If you go on you throw the remaining dice and have to put at least another dice aside and so a counter on a safe card.
If you stop you can take a safe card on which all code numbers are covered by markers.
If you throw only pits that are not on a revealed safe card your turn ends immediately and you get no safe card.