It was the Blue Diamond's first time to a marriage. Gems doing a human thing, that was a little unusual. But she figured since (many) Gems took on a human shape, it would seem appropriate for them to take on human activities, like...love. The Blue Diamond sat in the back so as not to obstruct the view of the others, as they all watched Steven act as the minister for the occasion.
"I now pronounce you Garnet."
They kissed, and fused back into Garnet for the first time in days. Everybody cried, either with genuine joy, or the Blue Diamond was making them cry.
Then something appeared from somewhere in the sky, and it got closer and closer. For everybody involved, it was something that was unfortunately familiar.

It was the Yellow Diamond's hand ship. Steven ran over to the Blue Diamond to take cover, and, maybe, ask her what's going on.
"What's going on?" he asked.
"I told Yellow what happened but she didn't seem to believe me."
The Blue Diamond stepped back, but stopped when they heard a crunching sound: The Blue Diamond stepped on the sword!Everybody was in shock. Then they looked back up to the Yellow Diamond's hand ship as it headed toward the barn, where the drill hole leading to the Cluster was. Steven's heart pounded, fearing what was going to happen next.

The Cluster, in the shape of a giant arm, emerged from the hole and engaged in an arm wrestle with the Yellow Diamond's hand ship. The hand ship, out of control, was launched in the opposite direction...straight into Steven's house. The Yellow Diamond herself emerged from the surviving portion of the ship, onto the thin layer of water below her. She slowly approached the crashed party.

"Blue," said the Yellow Diamond, "It seems you were right about the Cluster. But nevertheless, I came here to do this the hard way, and I'm not leaving until I've done so."
Steven sensed that the only way for the Diamonds to like him and the Crystal Gems (and, by extension, the Earth) would be for him to go out and tell the Yellow Diamond that he was the (son of the) long lost Pink Diamond. So he ran out toward the approaching Diamonds.
"STOP," he yelled as loud as he could, "I'm the one you're missing! I'm Pink Diamond!"
But he wasn't loud enough. He got stepped on by the Yellow Diamond.

Steven 'woke up' in a strange new area. He realized that he was in a literal state of unconsciousness. Around him were the auras emitted by the people and gems back on the beach. And in the distance were the Diamonds' auras. Steven jumped from aura to aura, with each one feeling a gust of his presence as he passed by. When he got to the Yellow Diamond's aura, he saw that it was stronger than the others, and therefore, harder to make a good-enough contact with. Nevertheless, he persisted. Holding his breath as if to swim, he slowly made his way into the Yellow Diamond's aura, and began to speak.
"Yellow!" he said, "Pink's fate is different than you think. She faked her shattering!"
The Blue Diamond recognized his voice, but couldn't see him.
"It must be Steven!" she said in delight.
"Who are you talking about, Blue?"
Steven was launched out of the Yellow Diamond's aura, but then looked down and saw that he was about to emit his own.
"Please!" he pleaded, "This fighting has to stop. We aren't enemies, We're family. Please listen to me...I need you to know...who I am!"

Out of energy and regaining his consciousness, Steven finally awoke. Before him were the Crystal Gems, his dad Greg...and the Diamonds. Both of them.
Steven was too weak to speak, but tried to anyway.
"I'm...sorry...for everything."
The Diamonds stood up straight, keeping their eye contact on little Steven.
"You are forgiven," said the Yellow Diamond.
"You are forgiven," said Steven in return.
The Blue Diamond picked him up and nuzzled her against her giant cheek.
"You are forgiven," she said.
And Steven said again "You are forgiven."

You are forgiven (You are forgiven)
You are forgiven (You are forgiven)
You are forgiven (You are forgiven)
You are forgiven (You are forgiven)
You are forgiven forgiven forgiven forgiven forgiven forgiven forgiven forgiven forgiven forgiven forgiven forgiven forgiven forgiven forgiven forgiven
FORGIVEN! FORGIVEN! FORGIVEN! FORGIVEN! FORGIVEN! FORGIVEN! FORGIVEN! FORGIVEN! FORGIVEN! FORGIVEN! FORGIVEN! FORGIVEN! FORGIVEN! FORGIVEN! FORGIVEN! FORGIVEN! FORGIVEEEEEENNNNNN!

It was decided that Steven go with them back to the Homeworld. Steven agreed, on the condition that Connie and the gems come with him too. The Diamonds were surprised to learn about the corrupted gems, how they were not completely obliterated as originally intended. Steven tried to heal a corrupted gem once, but it didn't stick. The Diamonds said the only way to do it would be for all the Diamonds to do it together. And that goes for the White Diamond, whom Steven had yet to meet.
They took the Blue Diamond's hand ship, which was still in working condition, to the Homeworld. Waiting for them was the White Diamond's pearl. She had seen better days.
"Pink Diamond," she said, "Your presence is required."
Only Steven was allowed in to the White Diamond's quarters. He looked up to see her in all her majestic glory.
"Baby!" she said, then with a dramatic pause, and finally slowly and operatic, "You arrreee forrrrrgiiiii..."
"Veeeeennnnn!"
Steven pointed at the White Diamond and said in response "You are forgiven!"
"You are forgiven!"
The White Diamond opened the doors to her quarters, allowing all the other gems and Diamonds inside.
They all said/screamed/sang "You are forgiven,"
Then they turned and approached the edge of the stage, and took a bow to their audience, as they continued with the repetitive "You are forgiven". The curtain lowered to a close, leaving just Steven standing there.
"We're all forgiven!" he declared.
(Applause)