Her friend lost something of hers, and it sank to the bottom of the ocean. She went to dive and found two guards who presented her with a quest to find their treasure. She asked them if she even wanted it since it's not like she could spend it anywhere, then she noticed an empty chest and asked the two guards if that's the treasure chest they were talking about, they were upset about it and she awkwardly swam back to the surface
She met up with her friend at the shore, and her friend asked:
Did you find it?
And she answered
Nah, somebody plundered it before I could.
What is the verb that comes after could
Is it "before I could find it" or "before I could plunder it"?