AppAdvice has teamed up with AppEndix in order to offer you a chance to win one of three promo codes for Sherlock Holmes ($0.99) for iPad, iPhone, and iPod touch.

Mysteries create excitement through curiosity and accomplishment. The process of following a tale of twists and turns, then guessing where it leads and how it all fits together is very satisfying, even when just reading or watching the story play out. However, what if you were directly involved, and your decisions made a difference on the outcome?

Not the traditional linear reading experience, this digital gamebook may have you jumping dozens of pages forwards or backwards to play out the story. In this dynamic tale, many steps are completely random while other outcomes are effected by your guesses, interpretations of clues, interactions with other characters, and so on. In addition, you’re immersed in sound effects, dramatizing music, and HD artwork.

First of the iOS releases of the Sherlock Holmes Solo Mystery Series, the Sherlock Holmes 1 app includes the Murder at the Diogenes Club mystery as well as a bonus, the Irish Star affair, for you to be apart of. In fact, AppEndix provides the opportunity to proudly earn Game Center achievements for completing the book and solving each case.

To have a chance at winning a Sherlock Holmes promo code, just hit that tweet button near the bottom of this page or retweet this post from your favorite Twitter app before Oct. 17 at 11:59 p.m. PDT. We will then search the Twitterverse for all of the retweets and randomly choose our lucky winners. The winners will be notified via Twitter, so please be sure to follow us so we can send you your promo code via a direct message.

Non-Twitter users and those of you who want to increase your odds of winning can leave a relevant comment below before 11:59 p.m. PDT tomorrow to have a chance at winning one of the other two Sherlock Holmes promo codes. If you do make an entry via the comments area, please be sure to also check your junk email boxes so that you won’t miss out if you win.

Feel free to participate in the giveaway via either or both methods. Only one entry per person per method is allowed, totaling up to two entries per person if using both.