Henry, feeling lonely on a street without any other children, finds companionship and love in a big dog named Mudge.

For Henry and his big dog Mudge, summer means going on a picnic in the park, taking a bath under the garden hose, and going to the top of the big green hill.

In the winter Henry and his big dog Mudge play in the snow, share a family Christmas dinner, and gather around a crackling winter fireplace.

When Mudge gets sick unexpectedly, Henry does all he can to make him feel better.

Henry worries about what will happen to his big dog Mudge during their visit to his grandmother's house in the country. Spending the night at grandmother's house, Henry and Mudge help each other through a scary nighttime adventure when a collection of unfamiliar sounds keeps them awake.

Henry and Mudge the dog's boring weekend becomes interesting when Mom suggests building a castle in the basement.

At first Henry's very neat cousin doesn't like the cookies from under his bed or Mudge's slobbery kisses, but when they all play frisbee, she begins to enjoy her visit. Best friends Henry and Mudge have a difficult time winning over Henry's cousin Annie, until they discover that Annie shares their love of frisbee.

Henry and his big dog Mudge attend their first family reunion.

Henry, his dog Mudge, and his parents go on a quiet camping trip to Big Bear Lake, enjoying the clean smell of trees and wonderful green dreams.

Mudge looks forward to the Mother's Day surprise that Henry and his father cook up for Henry's mother.

Henry is excited when his Uncle Jake builds him a tree house but worries that his dog Mudge will not be able to enjoy it with him.

Henry and his dog Mudge tangle with a grumpy goose when they visit a farm.

Henry, his dog Mudge, and his father enter a snowman building contest at the local park and win third place.

Henry, his parents, and his dog Mudge take a vacation out West, where they enjoy tumbleweeds, desert animals, souvenirs, and the wide open spaces.