What Do I Need To Know Before Infinity War? My Cheat Sheet
People have been asking me what Marvel films they should watch to prepare for Avengers: Infinity War, yet don't have the time to watch all 18 films that currently represent the Marvel Cinematic Universe. So, this is my cheat sheet.
This will have a level of spoilers so that I can explain why you should watch them. So, if you don't want to know at all before watching them, these are the films I'm suggesting.
Marvel's The Avengers
Captain America: The Winter Soldier
Guardians of the Galaxy
Avengers: Age of Ultron
Captain America: Civil War
Doctor Strange
Thor: Ragnarok
Black Panther
Read no further if you don't want spoilers.
Conversely, if you have no time to catch up by watching any of the films, you can use this as a recap.
Marvel's The Avengers
Marvel's The Avengers is what proved that Marvel's movies could do what made it's comics popular - living within a shared universe. The film brought together the major players of this universe (Iron Man, Captain America, Thor, Hulk, Black Widow & Hawkeye) as The Avengers. The film also introduces the mad Titan Thanos who is the main villain in Infinity War.
Captain America: The Winter Soldier
This film is important to show the destruction of S.H.I.E.L.D., the quasi-governmental organization that brought The Avengers together. It also shows Captain America's disillusionment with the government of today which will play into the eventual conflict between Tony (Iron Man) and Steve (Cap). The film introduces us to the Winter Soldier who happens to be Steve's best friend Bucky Barnes who was frozen on ice by the villainous group Hydra and brainwashed into being their assassin.
Guardians of the Galaxy
Guardians of the Galaxy is a critical film because it introduces you to several concepts important for Infinity War. Foremost, it explains to us the concept of the Infinity Stones (there are 6) which are being sought by Thanos to give him ultimate power. We learn that several artifacts in other films up to that time are actually Infinity Stones - The Tesseract from Captain America: The First Avenger and Marvel's The Avengers is the Space Stone, the gem in Loki's staff from Marvel's The Avengers is the Mind Stone, the Aether from Thor: The Dark World is the Reality Stone, and the Orb in this film is the Power Stone. Thanos appears in the film who bids the Kree warrior Ronan to get the Power Stone from the Guardians. We are introduced to two of his "daughters" (not biological, but last survivors of their races) - one is a member of the Guardians Gamora. The other is the villainous Nebula. More of Thanos's children will be introduced in Infinity War.
Avengers: Age of Ultron
This film shows Tony Stark's hubris in his effort to save the world. He creates an Iron peacekeeping force that polices for him when The Avengers can't. When he and Bruce Banner play around with the gem from Loki's staff, they inadvertently create Ultron, a sentient artificial intelligence who decides to save humanity by destroying it. Ultron then inadvertently creates The Vision, a physical manifestation of Tony's original A.I. JARVIS embued with the Mind Stone, who joins the Avengers to take down Ultron. During their battle with Ultron, the Eastern European country of Sokovia is destroyed and impacts the Avengers in many ways. The film also introduced another Avenger - Wanda Maximoff (Scarlet Witch). Her speedster brother Pietro (Quicksilver) dies.
Captain America: Civil War
In the aftermath of Age of Ultron, Captain America and Iron Man are at odds with each other when the government decides to support the Sokovia Accords which would put superheroes under the control of the United Nations in order to avoid more events like Sokovia. Tony, haunted by his creation of Ultron and the destruction of Sokovia, agrees with the government. Steve, having a certain level of distrust that government could eventually corrupt as seen with the infiltration of Hydra, believes The Avengers should have autonomy. When Bucky, who has been in hiding after the events of Winter Soldier, is framed for the assassination of the King of Wakanda (Black Panther's father), Tony & Steve are pitted up with each other with various Avengers taking sides. Cap also brings in Ant-Man and Tony brings in Spider-Man. But all this is orchestrated by ex-Sokovian soldier Helmut Zemo who wanted to tear the Avengers apart in revenge for the death of his family. Zemo reveals Bucky killed Tony's parents while brainwashed as the Winter Soldier and this tears the Avengers apart. T'Challa (Black Panther) offers refuge to Bucky who offers to use Wakandan technology to reprogram him to no longer respond to his trigger words.
Doctor Strange
This film introduces Doctor Strange who looks to play a major role in Infinity War. The film also introduces magic to the Marvel Cinematic Universe. Finally, Doctor Strange uses an amulet called the Eye of Agamotto, which can control time. This, we find out, is the Time Stone.
Thor: Ragnarok
Most of what you need in Thor: Ragnarok is that both Thor and Hulk are in space, having been enslaved into his Contest of Champions by an ancient being named the Grandmaster. This is why they are missing in Civil War. At the end of the movie, Thor tells Loki to put the Fire Giant King Surtur's skull into the Eternal Flame to bring Surtur back and begin Ragnarok (the destruction of Asgard) and destroy his villainous sister Hela. On the way to do this, Loki eyes the Tesseract which we know to be the Space Stone. The surviving Asgardians set course for Earth, but are intercepted by an ominous giant ship, most likely that of Thanos.
Black Panther
While we first saw Wakanda at the end of Civil War, Black Panther fleshes Wakanda out and introduces us to some characters who look to have a role in Infinity War, including T'Challa's general Okoye, his tech genius sister Shuri and Jabari Tribe leader M'Baku. We also learn that Shuri is able to deprogram Bucky who locals call White Wolf. From the trailers, we see part of Infinity War takes place in Wakanda with T'Challa welcoming Captain America and Black Widow.
If you can fit them in, I would highly recommend watching Iron Man, Captain America: The First Avenger and Thor just to properly introduce yourself to these key characters.
So, there you have it. I hope this helps anybody who needs it.