Why, one wonders, do comic-book villains so often attack the heroes in evenly matched sets, so that their inevitable defeat is, well, inevitable? In Under Siege, a large group of Marvel villains band together to completely overwhelm the Avengers, attacking them first individually, then hitting them with such great force that the heroes have no chance of winning.

And, for a while, it works.

Baron Zemo, son of the original World War II Nazi -- who was defeated during the war by Captain America, but not until after he caused the death of Cap's sidekick Bucky -- has conjured a plan to take out his father's star-spangled nemesis and all of the Avengers in one bold maneuver. He gathers a powerful and varied team of villains -- Mister Hyde, the Fixer, Goliath, the Wrecking Crew, Moonstone, Yellowjacket, Blackout, the Absorbing Man, Titania and plenty more -- and deviously plans an assault that takes out their opponents one by one.

Given that Under Siege is a collected edition, not a dedicated graphic novel, there is a lot of slow buildup and references to other storylines that, especially in the first half, bog the story down. The Avengers, unaware of the Baron's machinations, are dealing with other issues that won't pay off until later books.

But then the invasion of Avengers headquarters begins, and a cunning ploy has left the base undefended except for Jarvis, the butler, on monitor duty. Once the automated defenses are defeated, it's simple enough to take down the hapless butler ... and then it's a matter of picking off individual Avengers as they stroll into the building without a care.

The Black Knight is the first to fall, followed by Captain Marvel (the light-based version), then Captain America. Hercules, aware of the danger but uncaring, runs heedless into the fight and is beaten nearly to death. What follows is sometimes quite brutal, particularly the merciless beating of Jarvis as Captain America is forced to watch.

Soon, the headquarters is surrounded by police and the military but is inaccessible. The few remaining heroes -- Avengers leader Janet "The Wasp" Van Dyne, along with allies such as Thor, Doctor Druid and the second Ant-Man -- seek means to get inside and rescue their friends.

Of course you know they'll succeed, but getting there is quite the story. I remember when this story first came out, and it was a tense read -- waiting a month for each new installment, to find out what happened next and who, if anyone, might fall.

Which leads to an important question: Given that the villains here have no compunctions against murder, why do they leave their captive Avengers alive? They must know that, where there's life, there's hope, and the heroes will certainly find some way to escape or be rescued. And then their defeat is, well, inevitable.

Certainly, the excitement of this story lies in seeing how the Avengers snatch victory from their initial defeat. Still, one wonders what might have happened if the bad guys were truly as evil as they claimed.