The story is always some guy (sucker) trying to hook up with this girl (not a real girl likely, or if they are a real girl they are using pictures of someone else) through some app / website.

She asks him for money to help with surgery, or a family emergency, or paying debt, or whatever excuse they come up with. "I need to pay off this debt before I can leave my country, please send me $_____ and then once I pay them I will come meet you and we can finally be together!" "My mom is sick in the hospital and needs $_____ to pay the bill. I can't leave her like this, once the bill is paid she can leave the hospital and I can come visit you!"

The lonely desperate person pays the scammer and then they realize their mistake some time later.