Infinity is a six-issue event miniseries by Jonathan Hickman with art by Jim Cheung, Dustin Weaver and Jerome Opena. Building off of Hickman's run on Avengers and it's sister title New Avengers, Infinity forces the Earth's Mightiest Heroes to travel to the stars in an intergalactic war against their greatest threat yet: the enigmatic Builders, supposedly the first civilization in creation. While the Earth's greatest heroes are in distant galaxies, the mad Titan Thanos seizes the opportunity to launch a full scale invasion of the planet with his army led by his terrifying generals. Launching in August, the first issue will feature art by Jim Cheung who also handles the final issue in November. Weaver and Opena are on deck for issues 2-5, which double ship in September and October. Dustin Weaver does the art for the war on Earth while Opena does the war against the Builders in the cosmos.
Avengers, also by Jonathan Hickman, is considered one of the most essential tie-ins of the event and is pretty much required. Focusing on the war against the Builders, it follows Captain America's Avengers squad rallying an army of galactic allies.
New Avengers, the sister title, follows the war at home. Focusing on the Illuminati(Black Bolt, Iron Man, Mr. Fantastic, Dr. Strange, Black Panther and Beast) and their efforts to stop Thanos and save the Earth against the ever-present threat of multiversal incursions.
Avengers Assemble takes a more personal look at the Avengers in space, following individual members like Hawkeye, Black Widow and Captain Marvel caught in the middle of the war.
Captain Marvel follows Carol Danvers, Captain America' second in command, thrust once again into the cosmic world while trying to save the universe itself.
When Thanos' invasion hits in the middle of a mission to take down the New York mob, the Thunderbolts are forced to choose what is more important: killing the criminals they targeted, or saving civillians from the alien threat.
With the Avengers nowhere to be found, Luke Cage is forced to come out of retirement and form a new team of Mighty Avengers to help protect New York from Thanos' hordes.
During a friendly revival of the classic Contest of Champions tournament hosted by the various super-schools of the MU, Thanos' head general Corvus Glaive leads a personal assault and turns a friendly championship into a fight for survival.
Newly minted Nova Sam Alexander is faced with his second world-ending crisis when Thanos arrives on Earth. He tackles it the same as he did the Phoenix Force, by, well, tackling it. Sam will quickly find out that Thanos has a personal hatred for anyone sporting the name Nova, and is well out of his weight class.
Otto Octavius, the Superior Spider-Man, is forced to team-up with Beast, Wolverine and other heroes to stave off Thanos' massive army.
Other unsolicited but announced tie-ins include Guardians of the Galaxy and a few X-Men titles.