Luke flies his X-wing fighter to meet the rest of the Rebel Alliance, but first he has to make a pit stop on Dagobah.
Back on the Death Star, The Emperor arrives in grand, thoroughly evil fashion. He wears a black hooded robe and is super old—120 years old.
Vader tells The Emperor that the Death Star will be completed on time, and The Emperor's stoked. He also senses that Vader's anxious to get back to looking for Luke.
The Emperor tells Vader that he needs to be patient; Luke's going to come to them.
Also, Luke's gotten really strong, so strong, in fact that it's going to take both of their evil butts to turn the kid to the Dark Side. Then the Emperor cackles like a witch.
Cut to Luke at Yoda's swamp-side crib on Dagobah. Yoda's not looking so hot. He's old and sick, and he tells Luke to see how good he looks when he's 900 years old.
Luke tells Yoda he can't die, and Yoda says he totally can. He's strong with The Force, but not that strong. Nobody lives forever. That's the way things work.
Luke tucks Yoda into bed, stopping short of reading him a bedtime story. Then he says he still needs Yoda's help to complete his Jedi training.
Yoda tells Luke he doesn't need anymore training, and Luke assumes that means he's a full-fledged Jedi. Yoda corrects him: He's almost a Jedi, but he still has one little matter to take care of: Darth Vader. Then, and only then, will he be a Jedi.
Luke thinks on that for a hot second, and then asks Yoda if Darth Vader is really his dad. Yoda confirms that he is, and says it's a bummer that Luke rushed to face him already, when his training wasn't complete.
That's kind of confusing, given that Yoda just said Luke can't fully complete his training until he faces Darth Vader, but we'll allow it. (Dude is 900 years old, after all.)
Yoda reminds Luke that a Jedi's strength comes from The Force, and that anger and aggression are all on the Dark Side, and that if you go down that road, it's really, really, really hard to come back.
Then Yoda drops another truth bomb. When Yoda dies, Luke will be the last Jedi. The force is wicked strong in his family. Oh, and also? There's another Skywalker. Say what now??
Yoda passes out, and Luke's mind is blown. Then Yoda vanishes.