Shepard reaches for the Citadel console, even though she sees no other button to press, and collapses before she can solve the problem. That’s when the floor panel she lies on rises up and ascends.
She’s lifted to a new area, and there he is. It’s Boy, limned as a transparent computer construct. He chastises her. He’s in charge, the one who directs the Reapers to harvest mature civilizations. It’s the only way to save organic life. Eventually every species will reach a point where synthetic life will threaten them. Before all organics are killed, the Catalyst — Boy — looses the Reapers. Mature species are processed to become new Reapers. Immature species are left alone to develop over the next 50,000 years.
(Talk about an exposition dump!)
Shepard, if she wants, can ask questions and try to understand. Boy was created as a solution to conflict, an inevitable end between organic and synthetic. Nothing else worked, and so the Reapers were invented. The species that programmed Boy, Leviathan, became a victim of its own solution. Basically, Boy is an unshackled AI. (It’s an old scifi trope: the computer kills humanity in order to fulfill its programming to save humanity.)
However, Shepard’s presence has changed things. The Crucible, invented and improved over many cycles, is working for the first time. Activating it has changed Boy and made his usual solution no longer tenable. (I’m not sure why.) Now Shepard must choose.
One option destroys Boy and all synthetic life. That means that the Reapers are gone forever, but it also means that anything with a trace of machine, including Shepard herself, will also be wiped out. Technology will be gone, although people will be able to rebuild all that. Everyone still alive who isn’t part-synthetic will carry on.
Boy cautions against this solution because the age-old problem of created synthetics will return. Conflict will eventually come. (No option to question this truth exists. These are the rules of the Mass Effect world. Conflict is inevitable.)
Option B allows Shepard to take control of the Reapers, just as the Illusive Man always wanted. He was indoctrinated, so he could never be the one to do this, but Shepard can. She will die, but she will remain in charge. Basically, she becomes a god. She becomes the new Boy. No corporeal form, but her ethics and morality will direct the Reapers.
Either way ends with Shepard dead. Two paths lie ahead, one glowing blue for paragon, and one glowing red for renegade. (I have no idea which path is considered by Bioware to be the “good” one. I’m not even sure, if I had a clear idea, which path indicates which solution. On the first playthrough, since I’m playing Ace the Paragon, I’ll choose the blue end.) Shepard, after the molasses walk to end all walks — bathroom and snack breaks, everyone! — grabs the control panel and dissolves into an electrical storm of power.
We get a longing freeze frame of EDI. I think that means Shepard killed all tech. Normandy, racing ahead of the destruction bubble, crash lands on a lush planet. The mass effect relays are destroyed, each one sending the beam to the next before exploding. But then, when Joker steps out from the ship onto this Eden-like planet, EDI steps out, too. So, Shepard didn’t kill all tech, even though the Normandy went down? I’m totally confused.
The military troops fighting on Earth start to cheer as husks collapse and the Reapers retreat from the planet. Krogans have little cutie-pie babies and Shepard’s old teammates put her name on the Normandy’s wall of the fallen.
Then we see Reapers rebuilding everything. They swarm over the mass relays. They work like construction cranes on London. Shepard, in a god voice, talks over the images, speaking about how she’ll watch everyone, or something. Not only do I dislike this ending, philosophically speaking, but it’s such an information overload that I can’t follow it all.
Post-credits, we see an almost snow globe scene with an elderly man (the Stargazer, voiced by Buzz Aldrin) telling a child stories about “The Shepard”. Much time has passed and now . . . humanity has become primitive, educating itself with Shepard biblical parables? Did the galaxy rebuild?
Bioware killed my heroine for this?
I have a headache.
(Or, a true renegade like Tag can tell Boy to stuff it. Free will is what defines organics, and she won’t accept any of these solutions. She’ll fight on, even though there’s no longer a way to fight. Boy’s still in charge and the cycle continues. All organic civilizations are harvested by the Reapers. The last shot is Liara’s time capsule, a VI of herself, telling the next cycle of organics what we all did to try to defeat the Reapers. Maybe the next group of civilizations will succeed.
And, apparently, it does. This Stargazer is a woman who tells the child about “The Shepard”. She says that their world has peace because of her. The suggestion is that Liara’s warning was enough. This future cycle built on the accumulated knowledge of the Crucible and defeated the Reapers.
Of course, they just probably had someone who took Boy’s bargain.)