Ianto chewed on his lip for a moment, pausing, before he continued. "Cybermen are...well, from another universe, but they...are humans. Sort of. They're human minds transplanted into robot bodies. And...something goes wrong, in the process. They're not...they're not right. They're soldiers, and the only thing that they want is to upgrade more people to become one of them. Like the Daleks, they've got no emotion, but unlike them, surrender isn't going to save you from them. The choice is upgrade or die. And..."

Ianto took in a sharp, shaky breath. "There was this radar black spot high above London that Torchwood wanted to look into, so they build a tower to reach it. Then a sphere fell through, 'the Void' the Doctor called it, before, and it made a crack. A crack in the dimensions. Which is when the ghosts showed up. Just fuzzy images of vaguely human-like, whiteish figures. So Yvonne, the leader of Torchwood London, she started working on trying to open up that crack, letting more of the 'ghosts' come through. Only...we didn't realize that these ghosts were actually the Cybermen, fighting their way through from the other side. And that...inside of that Void sphere, a whole army of Daleks waited as well, for someone with enough energy from the time vortex to transfer some of that energy to it. Someone...like the Doctor and his companion."

Ianto swallowed, hard. "All... Apparently all it took was a little touch, and she opened the sphere and the Daleks were free. Just like all it took was the right amount of pressure and then the Cybermen were through as well..."