I like camphor and crazycatdude’s posts so I’m going to sort of cherry pick some of it.
Years after the Reaper War the galaxy faces a natural disaster as the black hole at the center of the galaxy begins expanding rapidly and it is believed that within the next few generations the Milky Way will be consumed. ARKON a private corporation focused on deep space travel and exo-technology (advanced alien technology) uncover galaxy jumping technology, but can only outfit a handful of ships.
The flagship of the fleet is The Shepard, a dreadnaught class colony/arc ship built for inter-species co-habitation and acts as a center of leadership/government for the fleet. There are also smaller ships meant for deep space exploration and scouting. One of these ships is a military vessel called the Tempest, which is headed by Commander G. Ryder.
Commander Ryder is a combat veteran with several decades of experience, but before he was chosen for this mission he was an instructor at the ICT on Earth and as part of his acceptance of this mission he brought along a number of his N6 students for their final exam.
When the fleet makes the jump however the experimental jump drive fails and the fleet then has the dual purpose of not only finding a new home for the races of the galaxy, but must also find a way back.
Commander Ryder along with his Krogan and Asari crew members pick a relatively habitable “wild west” planet to explore, but when their team uncover an ancient outpost they awaken the security systems and draw the attention of one of Andromeda’s many races who immediately attack the team. When Ryder and team retreat he dies saving the Asari crew member as they make their way back to the Tempest. With no other options Ryder’s student is promoted to lead the Tempest crew and find a new home in Andromeda.