The rats of the Dungeon of Rot #1

The good wizard Thunderbard was sunning in his garden when old king Thawmuch approached him one day. Thunderbard knew something was wrong. He asked the king, "How can I help you? Does someone need to be rescued?"

The king replied, "Yes, my brave daughter has been stolen from me by the bad wizard Stenchalot. She is being kept in the dungeon of Rot. Two horrible large rats guard the dungeon. Each rat is tied by a strong chain to the wall of the dungeon. The chains can be shortened by correctly setting some numbers on the machines that control the chains. Luckily, I found a book that shows part of the secret for setting the numbers. Once the chains are shortened you can squeeze past the rats and rescue my daughter."

Thunderbard looked calmly at the king and said, "I will do as you wish. Hand me the book and I will be on my way."

Thunderbard reached the dungeon before nightfall. He approached the first of the two rats. He saw the chain and its controlling machine. The machine had 10 squares cut into it that were arranged in a 2 x 5 grid. The ten digits 0-9, made out of cast iron, were lying in front of the machine. He opened the first page of the book and carefully read; "Place the ten digits 0 to 9 in the squares of the grid in a special way. Each square can have only one digit placed in it. First, the digits must be placed in order from smallest to largest in each row. Then, if you subtract the bottom digit from the top digit in each of the five columns, the answer must always be 1."

Thunderbard cheerfully tackled the problem.