Minecraft: Story Mode - Season Two

As for all Telltale games, you can import your save from the first season, which affects how the story goes in the 2nd season.

If you're after completing this achievement ASAP, open the spoiler. If you are after enjoying the story without spoiler, just continue playing as you would and this will eventually unlock.
Things might be a little different for you as choices affect how the story goes.

Story-based achievement, cannot be missed.