A new eShop-exclusive game called The Band of Thieves & 1,000 Pokémon will be available in Japan on June 5.

According to information from the Japanese magazine CoroCoro (via Serebii.net), the game is a tie-in to the upcoming Japanese release of the 17th Pokémon movie, subtitled Diancie and the Cocoon of Destruction. Its gameplay will involve collecting Pokémon via StreetPass to battle the titular thieves, who are said to be based on the characters Riot and Marilyn from the movie. Victory in these battles will be determined by the number of Pokémon the player has collected.

The Band of Thieves & 1,000 Pokémon will be free to download upon release, but will only be available for a limited time, from June 5 to September 30. At this point Nintendo hasn’t announced the game for Western territories, though a firm release date hasn’t been set for the new movie outside of Japan, either.