Mass Effect: Terminus (MA)

Shepard, hero of the Citadel, destroyer of Sovreign and conquerer of the Geth. But he wasn't the first alliance soldier to encounter the Geth, nor the Reapers for that matter, this is the story of one such ill-fated crew.

"Captain Hart, we've picked up an anomaly on the scanners above Casbin, it appears to be Geth!" exclaimed the pilot of the SSV Barrigada.
"The Geth haven't been outside the veil in centuries! what could they be doing out here?" exclaimed Raven
"Beats me, should we take a look?" asked the pilot.
"Citadel law prevents ships from landing there, it's a prehistoric Earth world." said the Navigator.
"Then the Geth really aren't supposed to be here, use the Grizzly, we're going in to take them out!" ordered Raven "Ground team, prepare for combat!" she ordered over the intercom. (Right now the crew is humans only but anyone who wants to join, they can encounter an alien who's also made it to the planet, or there's plenty of encounters later for additional alien characters)