I'll give you the cliff notes version:

They went to school with Mark Zuckerberg. They came up it Facebook together. It was the twins idea but Zuck wrote the code.

Fast forward a few years...

FB is worth a lot of money and the twins want their piece. After a legal dispute that went to private arbitration, zuck paid them off.

They took their billion dollars and put it all into Bitcoin back when it was still pretty new.

Later they put most of their Bitcoin into the Grayscale trust and used the rest to fund an exchange they set up called Gemini.

They've been waiting for years to cash out their Grayscale Bitcoin and now they can.