When an airplane from a secret airstrip terrorizes the performances of his friend Mr. Boomschmidt's circus, Freddy learns to fly, then gets a plane to track the criminals and stop their activities.

The show is interrupted by Mr. Condiment's lawyer, who claims that performer Mademoiselle Rose is endangered by the circus animals.

The Bean farm animals easily put the lie to that, but the show is interrupted again by a plane bombing with sacks of flour.

Finally the truth comes from Mr. Boom who "pretended to be a lot more simple-minded than he was so as to mix people up": Condiment is behind the disruptions: forcing Rose to marry him.

The flying instructor says he will be chasing a World War II fighter — faster than any plane Freddy can acquire.

Condiment is pressuring the bookstore owner into carrying his comics, including Lorna, the Leopard Woman, In the Lair of the Great Serpent.

Uncle Ben considers undermining enemies by selling them his defective bombsight, until Freddy discovers by accident that it is good at finding lost change.

For days, unseen, Freddy follows the mysterious plane, starting closer to its destination each time, and finally locating its secret airfield.

Without resources, they steal gunpowder from the criminals in a house by the airfield, and are highly pleased when they succeed in destroying it.

Freddy's detective partner, Mrs. Wiggins the cow, arrives in disguise, fooling him, and giving her the opportunity to say, "I know you!

In the moment of emotion, Condiment realizes he has a bargaining chip: in exchange for dropping charges, he informs Mr. Boom that Rose wants to marry him.

There are 36 black and white, pen and ink drawings by Wiese, endpapers, and a full color cover, both depicting scenes from the book.

An audio version read by John McDonough, running five hours on CD and cassette, is available from Recorded Books.