What does it look like?

Dd came rushing in with our first plum.
"I don't get it...there are 4 plums and we don't have another plum around to fertilize"
We've had this tree for 3 years and are still to get round buying another

As you can see it's very green as the wind blew it off.
So dd wanted to cut it open
"oh it's green inside too"
She picked it up and smelt it "what would it taste like?"...."yuck!"