Norwegian cartoonist Jason's book The Last Musketeer is the kind of whimsy that's easy to do wrong and nearly impossible to get right, but Jason gets it very right indeed.
Athos is an unemployed, destitute musketeer in contemporary Paris, reduced to begging for money to buy booze, when Martians begin bombarding France with a laser cannon. He runs to the home of Aramis, who long ago gave up musketeering and has become a contemporary Frenchman, and begs his old comrade to join him in a fight to save France from the Martian menace. Aramis insists that in the modern world, the President and his authorities can defend France, and there is no need for musketeers. Athos denounces him for a coward, accuses him of betraying the memory of Porthos and runs into the night.
Alone, Athos confronts two Martian invaders, killing one and taking the other hostage, demanding passage to Mars. But as soon as he arrives, he is overcome by the emporer's guard, and there begins the Martian campaign. Athos is jailed, escapes, wins over the evil emporer's beautiful daughter, destroys the laser cannon, and turns a killer robot into an ally.
It's a story that follows a dreamlike, comic logic, always silly and always fun, and every page has several large grins waiting to jump onto your face as you read.
Many thanks to the staff at Toronto's wonderful independent comic shop The Beguiling for recommending it.