by the entire Alliance fleet… it’s an impressive sight.”

“The fleet won’t look so impressive once it’s spread out across a few dozen star systems,” Grissom countered. “Our numbers are too small, and the galaxy’s too damn big.”

Eisennhorn had to admit that Grissom was probably more aware of that than anyone.

The technology of the Protheans had catapulted human society forward hundreds of years and allowed them to conquer the solar system. But it had required an even more amazing discovery to open up the vastness of space beyond their own sun.

In 2149 a research team exploring the farthest fringes of human expansion realized that Charon, a small satellite orbiting Pluto, wasn’t really a moon at all. It was actually an enormous piece of dormant Prothean technology. A mass relay. Floating for tens of thousands of years in the cold depths of space, it had become encased in a shell of ice and frozen debris several hundred kilometers thick.

The experts back on Earth weren’t completely unprepared for this particular revelation; the existence and purpose of mass relays had been mentioned in the data archives recovered from the Mars bunker. In simplest terms, the mass relays were a network of linked gates that could transport a ship from one relay to the next, instantaneously traversing thousands of light-years. The underlying scientific theory behind the creation of mass relays was still beyond the scope of humanity’s top experts. But even though they couldn’t construct one themselves, scientists were able to reactivate the dormant relay they had stumbled across.

The mass relay was a door that could open up the entire galaxy… or lead right into the heart of a burning star or black hole. Exploratory probes sent through immediately dropped out of contact — not unexpectedly, considering the notion that they were being instantly transported thousands of light-years away. In the end, the only way to truly know what was on the other side was to send somebody through; someone willing to brave the great unknown and face whatever dangers and challenges waited on the other side.