We open on Xandar being attacked by Thanos and his Black Order. Tons of Nova Corps officers are killed. Cull Obsidian is an absolute brute force. Thanos finds the Power Stone and smashes it into the crust of Xandar, wiping the planet out.
Cut to Thor's Asgardian ship being attacked by Thanos and his forces. Korg and Miek are killed but Heimdall and Valkyrie escape. Hulk attacks Thanos but is completely smashed and then thrown out into space. Thanos is about to kill Thor but Loki bargains for his life with the Space Stone. Loki also reveals that the Time Stone is on earth. Thanos takes the Space Stone, kills Loki and then sends his forces to Earth, Cull Obsidian and Ebony Maw to New York for the Time Stone and Corvus Glaive and Proxima Midnight after Vision and the Mind Stone.
Bruce crashes through the roof of the Sanctum Sanctorum and is discovered by Wong and Strange. Stark arrives having received a notification from one of his satellites and Bruce and Tony are reunited. Bruce explains who Thanos is to Stark whilst Strange and Wong explain what the Infinity Stones are. Tony suggests hiding or destroying the Time Stone but Strange is adamant that it is his role to protect the Stone not destroy it. Bruce says he should call Cap, but Tony explains that things aren't the same, also revealing that Vision has turned off his tracker and is completely off-the-grid. Tony gets the phone out to call Cap but is interrupted by the arrival of the Black Order's ship in New York. They walk outside to find Cull Obsidian and Ebony Maw. Spider-Man having seen the ship arrive whilst on a school bus, swings through New York to help Iron Man. Bruce is unable to transform into the Hulk. Ebony Maw fights Doctor Strange, capturing him and taking him to his ship. Iron Man sends Spider-Man to free Strange, but the ship starts leaving and Spidey cant breathe, passes out and begins to fall. Iron Man sends the Iron Spider suit which catches him and wraps around him. As Iron Man flies up, Pepper calls him and says he better not be on that ship, but he says he is and apologises before hanging up. He arrives on the scene and together they infiltrate the ship. Bruce finds the phone in the rubble and calls Steve.
Vision and Wanda are living in a safe house when Proxima Midnight and Corvus Glaive attack. Vision is almost killed but Wanda calls Cap and Cap, Widow and Falcon arrive and save Vision and Wanda. Corvus is killed and Proxima injured. They leave for Avengers HQ.
During this, the Guardians who have been tracking Thanos trail of carnage across the galaxy follow Thanos' to Knowhere. They find Thanos killing the Collector and adding the Reality Stone to the Gauntlet. They try and fight him but are easily defeated.
The Guardians find the wasteland of the Asgardian ship before Thor lands on their windscreen. He's brought inside, awoken and proceeds to talk with Gamora about who Thanos is and why he wants the stones, with Gamora having flashbacks to when she first met Thanos. Thor then suggests splitting up with himself, Groot and Rocket going to Nidavellir to create a new weapon for him to use. Star-Lord, Gamora, Drax and Mantis decide to follow Thanos.
Doctor Strange is tortured by Ebony Maw eventually losing the Time Stone, where its revealed that Maw is planning on keeping it for himself. Spidey and Stark locate Strange and rescue him. They stowaway on Maw's ship as it travels to Titan to rendezvous with Thanos.
Thor, Rocket and Groot arrive in Nidavellir and meet Eitri, the Dwarf King (played by Peter Dinklage). Together they are able to forge a new weapon, Stormbreaker, for Thor. They then travel to meet up with the other heroes in Wakanda
Bruce goes to the Avengers HQ and together they leave for Wakanda and upon arrival Cap and Bucky reunite. Shuri examines Vision. Cap and Panther talk about what to do.
The Guardians having followed Thanos to Titan meet Iron Man, Doctor Strange and Spider-Man on Ebony Maws ship. After a brief skirmish, they devise a plan to defeat Thanos. Thanos arrives, gets the Time Stone, kills Maw and reveals that he placed the Soul Stone deep within Titan, his home world, attempting to save it from destruction. He fights the Guardians, Nebula and heroes from Earth, nearly killing Spider-Man (which devastates Tony) and decimating the other heroes. Gamora and Nebula mount their final stand, but theyre killed by Thanos (who traps their souls in the Soul Stone).
Thanos send his Outrider ships to Wakanda. They arrive outside Wakanda and the Avengers travel to the front lines alongside the united Wakandan forces. Bruce is using the Hulkbuster because he can't turn into the Hulk. The heroes find themselves overwhelmed but they fight on. The Hulkbuster is overwhelmed by Outriders and Bruce hulks out. Eventually, Thanos uses the Space Stone to travel to Earth. He fights his way through the heroes (who make their last running stand as seen in the trailers). Scarlet Witch and Vision have stayed further back and Cap retreats to save them. He tries to hold Thanos off, but he's killed. Bucky arrives and charges at Thanos, shooting, but doesn't affect the titan. The Mind Stone is ripped from Vision's forehead and the Gauntlet is complete. Thanos leaves earth and returns to his ship, where he smirks before clicking his fingers.
t: Personally i really don't mind spoilers so i'm fine delving into this type of stuff.
