One of my favorite adventure stories!
A Lap family goes to the trading Post to trade some of their excess reindeer, but while they are there, the father is knocked unconscious in an accident. Seeing this as an opportunity, an unscrupulous trader changes their bill of sale from 30 deer to 300 deer; their entire herd.
To save their herd and livelihood, the son and daughter make off with the herd, branded as thieves but determined to save the reindeer until their father comes out of his coma.