Ok, let's see....
Christian did not get custody of the baby, but neither did the mother. The judge ruled for the father and his wife. Christian was very upset about it.
Sean was involved in an auto accident and subsequently started to take a few risks with his life, i.e., eating fugo (a potentially deadly fish) at a Japanese restaurant and going shark fishing with his son. One of the other divers had to be rushed to the surface with an embolism and Sean stayed on the boat to save his life. His son, who was calling him a ***** all show, was very much in awe of his father after that.
The show ended with Julia comforting Christian and then she told him that he already has a son, Matt.
So that's it, in a nutshell.