Based on a popular web-released manga series by Hidekazu Himaruya, this has been described as a "cynical gag" story set in Europe in the years between WW1 and WW2 (1915-1939), using exaggerated caricatures of the different nationalities as portrayed by a gaggle of bishōnen boys. For example, the Italia Veneziano character is into pasta and women. The Deutsche (German) bishi loves potatoes and sausages, and Nippon is an otaku boy. Installments of the manga have jumped back and forth in setting from the ancient times to modern-day geopolitics. The manga's title comes the Japanese words for "useless" (hetare) and Italy (Italia).
The Allied Forces, in their ongoing fight against the Axis Powers, manage to get ahold of one of Germany's prized possessions: an observation diary dealing with Italy's strange behavior and uselessness in combat.
The Axis are ambushed by the Allies once more, but another strange visitor arrives to break up the fight, with Christmas presents in tow.
Russia decides to jump out of a plane without a parachute, and England and France comment on how he broke all his bones. Then, the audience is introduced to the Baltics, although Latvia has a tendency to say the wrong thing at times. After that, America injures himself when England offers him some ice cream.
After having formed an alliance, England visits Japan's home but finds mysterious creatures that even Japan himself is unable to see or believe in anymore.
In a universe similar yet different from this one, three students at the Academy Of The World decide to survey the others on how they spend their winter holiday.
Germany wakes up to find himself visited by Italy's grandfather, the Roman Empire. But didn't he fall long ago? And is it a dream, or something stranger?
While camping out in the middle of a war front, Germany and Italy both make wishes on a shooting star, but which one will come true?
Italy shows Japan his combat record book (which turns out to be impressive in a different way), Germany decides to go sightseeing in Italy and attempts to blend in, the Axis are given special bentou, and Japan invents nikujaga. In another story, America ponders the mystery of who draws the sketches of the Axis and Allies on the blackboard.
Canada arrives late to a G8 meeting, but his absence and identity are barely recognized by the other nations. In another story, France decides to celebrate the Olympics.
America and Japan both prepare for the New Year and the coming of spring.
Russia and Germany form an alliance, while Italy fears that the other Axis Powers will eventually abandon him.
Continuation of The Pact Of Steel, along with more of Fly, Canada-san, Fly!
A baby America is discovered in the "New World", though this discovery also sets off a fight for ownership of him.
Continuation of The Battle For America: England and France continue their fight over the young America.
Adapts Big Brother France And The Information Manipulation Activities! and Reduce Your Opponents' Willpower, American-style!.
Russia tells the story of his sisters, Ukraine and Belarus.
Part two of the Russia's Big and Little Sisters story.
Switzerland tries to teach Liechtenstein self-defense. In other segments: Japan finds America's strange desserts photograph-worthy, while Canada (in more of Fly, Canada-san, Fly!) tries to tell America off but fails.
The origin of Liechtenstein is detailed.
England is the perpetual bed-head, and we go back to the past to remember a time when France was at his most flamboyant and mischievous - teasing England by showing off his long hair, and then cutting England's hair when his own plan to grow his hair long doesn't go according to plan.
England and France visit Poland, who has recently bought a fleet of ponies to help him in the war. In other stories: Chibitalia feels sad over the departure of Holy Roman Empire, while England finds that America grows up too fast.
England's latest secret weapon to win the war is a failure. In another story, Chibitalia finally grows up, but one change is a shock to Austria.
Adapts from Japan And The Footsteps Of Westernization, along with a segment from Fly, Canada-san, Fly!.
Adapts America's Situation With Ghosts.
Adapts more of Fly, Canada-san, Fly! and Holy Roman Empire's Playtime In The River.