Which of the Marvel movies are essential to rewatch before Avengers: Infinity War? With the epic culmination of the MCU just weeks away, fans want to get up to speed on Earth Mightiest Heroes, Thanos, and the Infinity Stones.

Of course, attempting to watch all 18 MCU films to get the full scope is a daunting task: that’s over a day-and-a-half of continuous movie time. To simplify matters, we have assembled the Marvel movies that must be rewatched to understand the main sweep of why Thanos is coming to Earth and why the Avengers must stop him.

These aren’t necessarily the best of the MCU, nor the most important; rather, they’re the films that best boil down the main storylines of the MCU relating to Thanos, the Avengers, and the Guardians coming to a head in Infinity War.

Just as there are six Infinity Stones, here are the six Marvel Movies that must be rewatched prior to Infinity War:

1. The Avengers. Earth’s Mightiest Heroes – Captain America, Iron Man, Thor, Black Widow, Hawkeye, and the Hulk – assemble for the first time to stop Loki and the Chitauri’s invasion of Earth. Joss Whedon’s blockbuster deftly juggles all of the major players of the MCU’s Phase 1 and deals with two Infinity Stones: the Space Stone (aka the Tesseract) and the Mind Stone. The mid-credits scene also marks the first appearance of Thanos, foreshadowing the Big Bad of the MCU.
2. Guardians of the Galaxy. The MCU goes cosmic as James Gunn introduces the major players in Marvel’s grander universe. Star-Lord, Drax, Gamora, Rocket, and Groot become a ragtag band of outer space heroes as they stop Ronan the Accuser from using the Power Stone (aka the Orb) to destroy the planet Xandar. Thanos makes his presence felt in Guardians Vol. 1, as does his “daughter” Nebula. The Collector (who has the Aether, aka the Reality Stone) also delivers the history of the Infinity Stones.
3. Avengers: Age of Ultron. The main story is the Avengers saving the world from Ultron’s android army but the film contains some crucial Infinity War set up: the Mind Stone leads to the creation of the Vision, Thor receives his own vision that sends him to space to seek the Infinity Stones, and Thanos makes his third appearance in the mid-credits scene to don the Infinity Gauntlet.
4. Captain America: Civil War. The Avengers break apart over ideological differences, which leads to the biggest superhero battle ever (until Infinity War). Black Panther and Spider-Man (the protege of Tony Stark) are introduced and, along with Ant-Man, they are all woven into the main story of the MCU. By the end, Captain America and his allies are in position for Avengers 3, with the end-credits scene set in Wakanda leading into Black Panther.
5. Black Panther. Wakanda will be a major battleground in Infinity War and the missing Soul Stone has long been rumored to be in the African nation. The fate of Bucky is also a puzzle piece Black Panther addresses.
6. Thor: Ragnarok. The God of Thunder’s cosmic escapades not only lead to a reunion with the Hulk and a brief encounter with Doctor Strange (who possesses the Time Stone), but also directly ties into Avengers: Infinity War; its mid-credits scene takes place moments before the movie begins.

If you watch those six films, then you’re be all up to speed. Obviously, there are several big movies we’ve omitted that definitely are essential to the overall MCU – Captain America: The Winter Soldier explores S.H.I.E.L.D. and Guardians of the Galaxy Vol. 2 deepens the Guardians’ family dynamics while teasing Thanos lightly – but don’t have a direct connection to Avengers: Infinity War. If you’re short on time before April 27, these are the movies you should be checking out.