Minecraft: Story Mode will be an episodic cinematic adventure that is choice and consequence based, like their other episodic series since the release of The Walking Dead. The developer of the block based sandbox game, Mojang, is working with Telltale to make sure the game feels like Minecraft, but they're not going to be establishing any Minecraft lore with this. They stated that they're "not intending on creating an “official” story for Steve (the player character in Minecraft), or explaining the world of Minecraft in detail".
No other details have been revealed yet, other than the platforms and general release date. The first episode will be released some time in 2015, and will be available on Xbox consoles, PlayStation consoles, PC, Mac, iOS, and Android-based devices.