Customers whoBlizzard's RTS expansion StarCraft 2: Legacy of the Void will be able to play three prequel missions right now, before the game launches in full this Winter.
Titled Whispers of Oblivion, the prologue features three story missions starring Dark Templar, who the Starcraft wiki tells me (I'm not big on the lore in this one) is a Protoss hero and has been a major character throughout the series.
The missions will bridge the story between previous expansionand Legacy of the Void. Don't worry if you're not the pre-ordering type, Blizzard says it will eventually make the prequel chapter free for everyone else as well. Pre-purchasing customers will simply get early access, as well as a spot in the game's ongoing beta test.
If you do fancy splashing your cash on StarCraft 2: Legacy of the Void, you can find all the relevant. The game comes in two forms, a £29.99 standard edition, and £44.99 digital deluxe edition. The latter adds a few customisation trinkets for Starcraft 2 and other Blizzard games.