Donald is the sole heir of his distant uncle Eustace Quack. Unfortunately, the heritage consists of nothing but two old books, a busted padlock and three tins of sardines stamped 1918. Suddenly a 70 years old I.O.U. slips from one of the books – a debt of 100 dollars, signed by Scrooge McDuck. Huey, Dewey and Louie quickly figure out that the sum is amounting to $2897.07 with compounded interest now. The Ducks hurry directly to Uncle Scrooge to pick up the sum. When the old skinflint learns about his debt he flees through the secret passages of the money bin. However, the nephews find the passage and catch up with Scrooge. On the roof the tightwad now remembers that he has lent Donald $2900 for repairing his roof. Donald has to pay the difference of $2.93 at once. The eternal loser is still lucky when an antique dealer buys the sardine tins for $5000.