I have to hand it to the writers of Stargate Universe. They really made something interesting out of what began as a stock time travel plot. While the weirdness of "Twin Destinies" at first seemed designed to do some leg work, like removing guest star Lou Diamond Phillips and closing up Eli's inner-star gating theory, "Common Descent" lets the time travel have larger implications for the plot and overarching philosophy of the show. After another drone attack forces Destiny to jump to the nearest gate world, the crew discovers a planet inhabited by their own descendants. Or, more accurately, the descendants of the version of Destiny that attempted the inner-star dial.
There's a whole lot of exposition in "Common Descent" that I would have rather seen play out in flashbacks, but that would have been a major undertaking for the crew, not to mention the budget, of the series. Something tells me they already broke the bank constructing fake log cabin sets and putting Louis Ferreira in old man makeup. Long story short, when the other Destiny's crew went through the gate, they found themselves transported back 2000 years and to a completely different planet, which they named Novus. They eventually built an entire society that fractured into two different countries within a generation. One follows Young's teachings of tolerance and pragmatism, the other takes a quasi-religious bent and awaits Rush's return on the Destiny. Political pressure and geological disasters force Novus to establish a colony on another gate world, but the new colony gets cut off when the Stargate back to Novus stops working.
The modern-day Destiny stumbles upon the colony, being met as ancient heroes everyone recognizes from Kino footage. Before they can settle the inevitable debate over whether or not to take the colonists on board to bring them back to Novus, if it still exists, the drones arrive again and force them to jump away, stranding some of Destiny's crew on the planet.
Using some admittedly clever tech, Eli solves this problem almost immediately, which would be frustrating if a more interesting problem didn't rise shortly after. With all of the surviving colonists hanging out on Destiny, it's only a matter of time before a quick shuttle ride through the metropolis on Novus reveals that the entire civilization seems to have been wiped out by volcanic activity.
There are a lot of interesting things at play in "Common Descent", from the background story of how the alternate timeline crew established an entire civilization to the implications that today's personal squabbles can echo through the centuries to become full-blown wars, but the more immediate issue is the ethical mess of how much today's Destiny should or can help their own descendants. The ship's resources are too limited to support them and their home is uninhabitable. On a large enough scale, when ethical concerns involve whole civilizations, personal ideals don't seem to even count. There's a lot of emotional weight here and some damn interesting stories. Too bad fewer than a million viewers even care to tune in to watch it play out.
Best Moment: Past-Eli's last Kino recording. Danny Blue really knows how to make an emotionally nuanced character and I hope he gets decent gigs after SGU closes up shop.
Notes: Remember the Neat-O Factor? Camille Wrey chatting with her own direct descendant? Neat-freakin'-O.
Episode Rating: 4.5/5- Loads of exposition and crazy-fast plot progression aside, "Common Descent" proves how much storytelling potential was always in SGU. Talk about too little, too late.