Mimes, a blimp and an inflatable dress all make the posthumous novel “Ira Foxglove,” by Thomas McMahon, a fantastic tale of midlife crisis set in the 1970s.

Ira Foxglove is a middle-aged science teacher and inventor abandoned by his wife and in constant pain from the complications of a heart attack. Having sold his greatest invention, a fabric made of tiny balloons that can inflate, for a mere $500 to his young, rich friend Neptune, Ira is all but washed up.

“Ira Foxglove” gets off to a quick start, but the story settles down into a mediocre pace after the first few chapters.

Ira’s wife, Portia, left him because she was tired of taking care of him after his heart attack. She sends him postcards from London, where she lives with a new boyfriend, and asks for money.

His daughter, Henley, to whom Ira is very close, is taking classes at a mime school in Paris, and also requests money frequently.

Though some of the characters are portrayed physically as intriguing and interesting, McMahon misses the mark in rounding out their personalities.

Portia and Neptune, for instance, both have quirky hobbies, but the extent of their depth stops there.

Neptune, in an effort to advertise the inflatable dress invented by Ira, decides to paint the side of a blimp with the slogan “Feather Fabric” and fly it to London, via Iceland. Ira goes along for the ride across the Atlantic to pay a visit to his wife and daughter.

While in Europe, he meets his wife’s boyfriend, plays a part in one of his daughter’s mime performances and has an awkward romantic encounter with Henley’s roommate Peaches. Ira is also inspired by a tomato to create an artificial heart.

The novel is far from engaging, possibly because the characters are rather flat. There’s never much empathy for Ira, nor do we see any motivation behind some of his actions.

“Foxglove” is whimsical in the strain of Kurt Vonnegut, and many of Ira’s encounters liven up the novel a bit. It’s hard not to laugh at Neptune fishing off the balcony of his blimp. Whimsy alone, though, is not enough to carry the novel.

McMahon renders dialogue naturally, and even though the characters themselves were flat, their interactions with each other were, in the least, realistic.

“Ira Foxglove” is a nominally interesting novel with a few redeeming elements and memorable scenes, but on the whole — not a recommended read.