Blake Belladonna finds herself in the hellish yet beautiful dystopian city of Rapture, at the behest of a certain pair of dimension-prowling twins. Armed with nothing but her wits and whatever she can find, Blake sets out to complete a dead man's journey while dodging the ADAM-starved freaks of Rapture. While in Rapture, Blake will learn a startling revelation about her past...

When her Council-funded expedition goes horrifyingly wrong, Liara T'soni must find a way back home. But she is caught up in the battle against the Combine, an inter-dimensional empire of immense power. Alongside Gordon Freeman, she will overthrow the combine to ensure humanity, and the galaxy's, survival against the Combine. But bigger powers are at play here. Much bigger...