The video outlines a world ravaged by the evil android.
"Evil has triumphed over good and leading this new age is none other than Ultron, the deadly sentient robot created by founding Avenger Hank Pym, who turned on his creator to achieve his twisted objective... the utter destruction of humanity," said the publisher.
"Now, it's up to the few remaining heroes to band together and find any way to topple their new monarch. Can Wolverine, Emma Frost, Invisible Woman, Taskmaster, Beast, She-Hulk, Luke Cage, Spider-Man, and Moon Knight turn the tide?
"With the robotic revolution in full force, no fan can miss how Age of Ultron will ultimately change the Marvel Universe leaving no hero or villain unscathed!"
Marvel has also teased the tie-in issue Uncanny Avengers #8AU, which teams regular writer Rick Remender with Deadpool's Gerry Dugan and artist Adam Kubert.
The issue will see time-travelling Avengers foe Kang enter the fray alongside the mysterious Apocalypse Twins.
Age of Ultron will debut in March. Uncanny Avengers #8AU will arrive in May.