Detective Pikachu is out now across Europe and the US for the Nintendo 3DS. To coincide with the launch, a free Pikachu iMessage sticker set is now available on iOS, but if you’d like to know more about the “great detective”, an illustrated prequel story has also been released as an ebook.

The game has Tim Goodman looking for his missing father, Harry, in Ryme City. Upon arrival, Tim meets and teams up with Detective Pikachu, looking for clues, talking to witnesses and uncovering secrets.

Nintendo has released a prequel story to the game, Detective Pikachu: Episode 0—Eevee’s Case. The book was originally released as a physical bonus for those who pre-ordered the game at a Pokémon Center in Japan. The short story is written by Detective Pikachu himself and tells how Eevee turns to the great detective, asking him to help find the culprit who messed up the yard at its home. In order to get to the bottom of the mystery, Detective Pikachu must chat with many other Pokémon as he explores Ryme City.

The story is available to download and read for free at Apple iBooks Store and Amazon’s Kindle Store for a limited time until 15 May.