Maybe a bunch of Decepticons kidnapped Willy, and John had to pay a ransom of eight bajillion dollars, but Willy escaped out of a nearby window in his captor's abode and fell down a fire escape before John had to pay the price and Willy walked all the way home, being the brave little puppy he is?
John did tell us!
A big dog stepped on him at puppy school!
(oh, hang on, ... have I missed the point of the question? If so, then let me rephrase that to say ...
An evil decepticon dog stepped on Willy at puppy school. Could be a story in that! "The adventures of Willy the nerdfighting puppy at Dogwarts the puppy school")