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.

Henry and his big dog Mudge try to keep busy inside the house during a thunderstorm.

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.

Henry and his big dog Mudge attend a family reunion.

While trying out the spy glasses, spy hat, and other items in their new spy kit, seven-year-old Henry and his dog Mudge make a new friend and form a spy club.

While Henry's parents are at a Sweetheart Dance on Valentine's Day, he and his dog Mudge have a wonderful time staying at Mrs. Hopper's house, where they enjoy tea and music and dressing up in various costumes.

At Christmastime Henry and his dog Mudge enjoy baked treats, visits from relatives, lots of presents, and each other.

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.