Originally conceived and announced as Avengers: Infinity War Part 1 & Part 2, the stories have been split apart a bit more.
"I'm less exhausted and excited 'cos I don't know what happens and you know, a little jealous..."
It's big and noisy and will make absolutely no sense to newcomers, but Infinity War is a devastating pay-off after years of slow build. He is Thanos (Josh Brolin), an extraterrestrial overlord who believes that the universe is overcrowded and aims to halve the population of every planet by gaining control of all six Infinity Stones, which have been scattered annoyingly throughout the other Marvel films. He's a tough bag guy. "If he gets all of the stones, he can do it with a snap of his fingers, just like that", says Gamora, played by Zoe Saldana.
That means its' up to Earth's (and the Galaxy's) mightiest heroes to stop him.
It was hard to watch and wasn't fun, but it brings up a big plot point: What's going to happen to everyone who we watched die? But in "Age of Ultron", it is eventually placed in Vision's head.
"Infinity" is an interesting word for the Marvel machine, which sets much of its development pipeline a decade in advance.
Thanos is the main character of this film which makes sense because there are too many other main characters to do them justice so the focus needed to be on the motivations of the villain. "I never would've gotten "I, Tonya" without Marvel", he explained. The Russo Brothers could have chosen anyone to be guarding the Soul Stone, they picked Red Skull (and Ross Marquand) - now we have to wait and see why they chose to do what they did.
Marvel wants you to feel that the stakes are high, that no-one is safe, that any one of your favourite characters could get smushed to death, presumably ending their potential for future franchise appearances and the associated commercial benefits. Samuel L. Jackson's Nick Fury - first seen in the post-credits scene of the aforementioned Iron Man, and not seen since 2015's Avengers: Age of Ultron - is in a vehicle with Cobie Smulders' Maria Hill - also not seen since Age of Ultron - responding to the attack by Thanos' forces on Wakanda. The Guardians, who inject most of the life to "Infinity War", swoon for Hemsworth's one-eyed Thor.
In a recent interview with GQ, the 35-year-old actor opened up about his bumpy ride in the film industry, the auditioning process and the fact that he nearly went bankrupt.