Heatwave is the thirty-seventh episode of the first season in The Mr. Men Show. This episode centers around a the Mr. Men and Little Misses surviving from a heatwave.
- Miss Calamity's plot: Miss Calamity's fan breaks off the ceiling and develops a killing mind of its own! Miss Calamity tries to get away from it. She calls the Dillydale Ceiling Fan Company, but it is no use. It soon sends her house off the cliff, even breaking her gnome.
- Mr. Persnickety's plot: Mr. Persnickety's radiator breaks down on the way to the beach and he is with Mr. Messy who makes a big mess.
- Mr. Nervous' plot: Mr. Nervous imagines that he landed an air craft on the planet mercury closest to the sun then a robot comes out shooting lasers at him. In reality he is being sprayed by Miss Scary's hose.
- Mr. Rude's Plot: Everyone in Dillydale knows that Mr. Rude has an air conditioner (it was Miss Scary who spread that rumor) and everyone barges into his house.
- Mr. Nervous' plot is absent in the UK version.
- Goof: The ending of the episode doesn't audicate properly in the UK version.
- The show that Mr. Small watches in Mr. Rude's plot is an actual episode from Fair.
- Goof: How did Miss Scary actually hear Mr. Noisy tell Mr. Strong about Mr. Rude's air con?