Sam and Donna are married.
They are both so happy. They leave the little island for their honeymoon. They remember that the bank of Greece is as dead as the dead sea. So, they end up moving from Greece to Israel. But then they move to Italy because Donna loves pasta.
Sophie and Skye are traveling the world and after going to Tokyo, they visit Sam and Donna. Sam adopted Sophie so she is so excited to see her mom and dad. She loves being able to call him dad. They go out for dinner at a nice restaurant and then later, a blizzard hits. They get trapped in their apartment. Finally Sophie pops the question.
"Sam, can we please get a DNA testing to see if you are really my dad?"
Sam's brown eyes shined gold.
"Of course."
Sam was nervous because what if he wasn't actually her biological father.
Sure enough, Bill is Sophie's biological father, not Sam.
Since it's not actually Sam it gets super awkward between them all.
Then Donna says, "You know guys, a father is different than a dad. A dad is there for his daughter always. And Sam's the one here right not, not Bill."
They give a group hug. Sophie and Skye then get married and move in with Donna and Sam. Donna likes having them home. Sophie helps out. Skye turns to drinking and becomes a couch potato. His addiction gets better and they all live happily ever after.
The end.