If you watch CSI: Crime Scene Investigation and play CSI: Crime City on Facebook, publisher Ubisoft has a great promotion coming up that links the two crime dramas together.

It works like this: by watching the show, starting with tomorrow’s episode “The Two Mrs. Grissoms,” players will be able to find answers to questions that wil be posted in the game. And the only way to find the answers is to watch. Entering the correct response will earn players UbiCredits, which can be used to buy energy in the game.

The questions have already been posted on the game’s Facebook page and the promotion will last for a month, covering four episodes of the show. And it doesn’t look like the questions will be easy. If you want those UbiCredits you’ll need to look closely to find things like the serial number on an alarm and the initials on a notebook. Then again if you both watch and play CSI, you probably already have a strong eye for small details.