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.
"Today is Halloween and Nancy can't wait to collect candy from each house she visits. But it's hard to leave all those delectable treats in her pumpkin pail. Is there such a thing as too much candy?" --
Mrs. Frizzle introduces some of the amazing animals who inhabit the Arctic and Antarctic regions, and explains how they have adapted to their icy homes.
A trip to the ocean becomes a search for the connection between Arnold's soggy shoe full of pond scum and Keesha's tuna fish sandwich. The bus shrinks and travels through the ocean food chain--getting eaten along the way!