The two Moffs played by Lee and Reed (or similar) rush the Imperial copy of the Life Star to completion, despite considerable losses in the workforce - so many that some workers spit ironically, "The rebels build a Life Star and it turns out to be more of a Death Star than we ever came up with." But completed it is, and moves out of Imperial homeworld orbit accompanied by a massive fleet of warships, bound for Yavin. "The Life Star will render their defences inert, and then the fleet will smash their capital. Didn't the fools ever hear the old proverb about keeping all their eggs in one basket?" mocks the Grand Admiral.
Meanwhile, Luke, Leia, and Han reach Bespin, soaring down to Cloud City. Luke has calmed, but Leia and Han are still anxious, both of them hoping that they'll find Laurel and perhaps give Luke some measure of peace after all that he's lost. Luke, for his part, has realized that Vader showing up on Gatta Prime almost certainly means that he picked up the trail on Tatooine...and likely killed his friends. He shares his anxiety with Leia, who can do nothing to allay his fears; she knows he's almost certainly correct. But then they're landing on Bespin, and as they leave the shuttle they're greeted by an old friend of Han's one Lando Calrissian, the manager of Cloud City. Han explains why they've come, and Lando smiles widely.
"Laurel Sundiver? Yeah, she's here. She's my right-hand woman, the best all-around tech and problem solver I've ever seen," he says. Luke, delighted, grabs hold of Lando by the shoulders, demanding to see her immediately.
"Whoa, calm down there, friend," Lando says. "I'll take you right to her."
Lando guides Luke, Leia and Han to his office, offering them refreshments then summoning Sundiver to his office. Han and Leia are all smiles, trying to support an increasingly nervous and tongue-tied Luke. Sundiver arrives, a lovely creature despite her unkempt uniform and carbon scoring dirtying her hands and face. She eyes the newcomers quizzically, offering them a tentative smile.
"Laurel, these people have come a long way to see you," Lando says. But before he can say more, Luke leaps to his feet.
"I'm Luke Skywalker," he blurts. "Ben Kenobi sent me. I'm your son.
Sundiver reacts with a mixture of delight and disbelief. "Luke...Luke?! But...the war's not over...Darth Vader is still - "
"Darth Vader is dead," Luke says. "You don't have to worry about him anymore. We can be a family again."
They embrace. Han and Lando are all smiles, while Leia holds back tears of joy.
But it's chaos on the green moon of Yavin. Thanks to sheer good luck, a Red Squadron patrol led by Wedge Antilles has detected the Imperial Fleet just a parsec away. General Dodonna orders rebel defences hastily mobilized, including the incomplete Life Star. With communications jammed, he sends a runner to the Millennium Falcon, with orders for Chewbacca and R2-D2 to get word to Princess Leia, wherever she may be; if the green moon falls, a resurgent rebellion can only coalesce around her leadership.
Chewbacca and R2 escape on the Falcon just as the Second Battle of Yavin begins. The Imperial Life Star exits hyperspace and blasts half the rebel fleet, knocking out its electronics and leaving the ships drifting helplessly. But Wedge's advance warning allowed the rest of the fleet to disperse, a small complement protecting the retreating rebel Life Star with the bulk assembling a hasty assault on the Imperial duplicate. But Chewbacca and R2 can see that the battle is almost hopeless. Reluctantly they jump to hyperspace.
Wedge leads a valiant assault on the Life Star and the Imperial fleet, and despite the incredible odds, the hard-fought battle ends in a devastating draw, with the Imperial Life Star crippled and several Star Destroyers themselves destroyed - but at the cost of most of the surviving rebel fleet. And enough Imperials have survived to start landing troops on the green moon of Yavin. Before the base is overrun, General Dodonna orders Wedge to escort the rebel Life Star to safe harbour, and to regroup with Princess Leia whenever possible. Wedge wants to stay, but he can see that it's hopeless - better to retreat and live to fight another day. Wedge and the half-built Life Star and a few remaining rebel ships jump to lightspeed as the green moon of Yavin burns. One of the Grand Moffs (Lee or Reed, it hardly matters) watches with a smug grin as AT-ATs overrun the main rebel base. The Empire is well and truly back.
The film's denouement takes place on Bespin, Chewbacca and R2 having followed the same trail to Bespin as the others. The awful news is shared all 'round, with Luke and Leia berating themselves for not being there during the attack. But it's Laurel who shares the final words of wisdom:
"Perhaps the Force guided you all here," she says. "If you'd been in the Yavin system, you would have fallen with the others. But you all live, and with you also lives a beacon of hope. Darth Vader is dead, the Empire is still a shell of its former glory. Your friends here say that some of the rebel forces escape. Find them, regroup, resist, and never surrender. Trust in the Force and find your finest hour."
With all aboard, the Millennium Falcon leaves Bespin, jumping to lightspeed as the final credits roll.