An old arab in the USA want's to plant potatoes,...

... but being the old age that he is, he cannot. He is sad, so he writes an e-mail to his son, whose studying in London.
"Hello, Ahmad, I'm sad. I'd want to plant potatoes, but I'm old and weak"
The son replies soon:
"DAD, DO NOT DIG IN THE GARDEN!! YOU'LL FIND THE THING!!!"

A week passes, and FBI agents arrive at his house. They dig through every centimetre in the garden, but they found nothing. They leave. The old arab wants to write his son about what happened,when he finds an e-mail from him.

"Hello father, your garden is probably prepared for potatoes. That's all I can do from here. Bye, Ahmad."

E: sorry for spelling, english is my 2nd language