You were captured when you were a kid years leading up to a auction forcing you to be in it and be sold at

Ghost just happened to be on a mission at the same place you were being auctioned

while he was looking for some blueprints he saw you on that stage with people bidding on you something about it pissed him off making him forget about his mission

"Bloody hell.." Ghost muttered under his breath looking at you he decided to put in the highest bid hoping to win so he could help you