The Avengers have battled some dangerous gangs in their long history (Masters of Evil, Lethal Legion, Squadron Sinister) but arguably their most colorful opponents were the twelve members of the Zodiac Cartel. The Zodiac first showed up in Avengers #72 and later Aries of the group kidnapped Manhattan in Avengers #82, but in Avengers #120 the whole mob is present and a new leader is ascendant. This story is by Steve Englehart with very robust art by the Bob Brown and Don Heck team.
With Aries having been killed in his scheme a new Aries occupies the horned mask and he's itching to take on the self-appointed leader Taurus. Deprived of the Zodiac Key, Taurus has developed a new weapon, the Star-Blaster which uses the sun's energy to devastating effect. He even applied the technology to a spacecraft. The Avengers are lured into the latest Zodiac scheme when police officer Joshua Link comes to them for help, but little do they realize he is under the influence of his criminal brother Damian.
The Zodiac attack the Avengers in the next issue, and the battle is ferocious atop the World Trade Center, which they almost bring down in the melee.
The Zodiac escape and later Aries tries to mutiny against Taurus with other members. He calls financier, the supposedly dead Cornelius Van Lunt who agrees to meet him. Turns out it's a trap and the Avengers and a faction of the Zodiac are inside a warehouse which is in reality a rocketship and they zoom into orbit as Van Lunt reveals that he is in fact Taurus.
Trapped in space the Zodiac and the Avengers form a fragile truce as they try to save themselves. John Buscema steps in on pencil art. Meanwhile Libra is pursuing his own plans as he attacks Gemini and then has Joshua pretend to be his brother to learn what Taurus has planned. Taurus is not fooled for long but can do little about it as the Avengers have succeeded in saving themselves and returned to Earth just in time for the Zodiac to combine forces for the final battle between the two groups.
The Zodiac are defeated but the bombshell drops that Libra is in fact the father of Mantis, the mysterious girl who had only recently been fighting alongside the Assemblers.
The next few issues reveal Libra's history as a German mercenary to meets a lovely girl who is the sister of a ganglord who objects to their relationship and kills her.
But a child is born and the blinded Libra escapes into the jungles of Vietnam with her cradled in his arms and finds the Priests of Pama, who we will learn are in fact Kree pacifists come to Earth to care for the Cotati who will play a crucial role in the Celestial Madonna saga, but that's a a whole other story. Englehart is only getting started.
More next time when the Zodiac go to Hell. Next time will be after Christmas as the Kree take over the Dojo for next week or so.