After having apparently forgotten about the brother they'd left behind in Egypt, the grain stores ran dry and Israel (Jacob) wanted his sons to go back to Egypt to buy more. They were not excited about this.
They begged their father to let them take Benjamin with them, so that that mysterious Egyptian grain-seller wouldn't, you know, kill them. In this part of the story the threat they mention has only to do with being unable to buy grain if they did not show up with Benjamin.
Israel, told them to take lots of bribes with them, and the silver that had been returned in the grain sacks, plus enough silver to buy more grain. And Benjamin tagged along.
When Joseph saw they had come back, he told his steward to prepare a feast for them all so they could eat together in his home.
When Joseph's steward showed the brothers into the house they got paranoid that it was all some sham meant to lull them into a false sense of security. Surely that creepy Egyptian was going to jump them!
They asked the steward about it, telling the man that they had all the silver that was mistakenly put back in their bags with them, that they were gonna give it back, honest! But the steward told them they were being paranoid and then he brought Simeon out to them.
Oh, so Simeon was the one they'd left behind. Well, I'm sure he was happy to see his brothers. The bastards.
They were given water to wash and their animals were put up, and the brothers bustled around getting all their bribes ready so that the creepy Egyptian would sell them grain and not hurt Benjamin.
When Joseph arrived for the meal, his brothers drowned themselves in obsequiousness, showering him with their bribes and prostrating themselves before him. They really laid it on thick.
Joseph asked about his father and they replied that he was well, and then Joseph spotted Benjamin, his little brother, the baby that his own mother died delivering. Oh, is this the youngest brother, you've brought him with you?
Joseph abruptly left the room to go weep somewhere. When he came back they ate.
But not together. Each group had its own table and was served separately. And Joseph made sure that, even though the youngest, Benjamin was served the most food.