Infinity War: Nothing but Spoilers

The following contains spoilers. Lots of them. You've been warned.

image courtesy of Marvel/Disney

Thanos got the power stone before the movie begins so Xandar has already been decimated.
Most of the Asgardians are dead and Valkyrie is nowhere to be found.
Thanos beats the crap out of Hulk, murders Heimdall and Loki, takes the space stone, then leaves Thor as the only survivor behind moments before the Asgard refugee ship explodes.

image courtesy of Marvel/Disney

Groot is now a teenager who does nothing but play a handheld video game all day.
Star Lord and Gamora developed a relationship.
Rocket is still sarcastic.
While responding to distress signal, Thor lands on their ship. Once inside he wakes up.
Thor keeps calling Rocket "Rabbit" and thinks he's the captain.
Rocket and Groot take Thor to Nidavellir to forge a replacement for Mjölnir.
Star Lord, Gamora, Drax, and Mantis travel to Knowhere to prevent Thanos from getting the reality stone from the Collector.
Tobias Fünke is in the Collector's collection. After he blue himself.
Surprise, they're too late; Thanos already has the reality stone.
He captures Gamora who is the only one who knows the location of the soul stone.
Star Lord, Mantis, and Drax go to Titan in hopes to rescue Gamora there.
On Thanos' ship, Nebula is being tortured. Gamora gives up the location of the soul stone to save Nebula's life.
They travel to the planet Vormir to retrieve the soul stone.
The Red Skull is there. The tesseract transported him there at the end of Captain America: The First Avenger.
To get the soul stone, Thanos must sacrifice the thing he loves most.
Gamora laughs because she thinks Thanos doesn't love anything.
Surprise, he loves Gamora, his favorite daughter. So he kills her to get the stone.

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The bifrost transports Hulk to Earth but he's transformed back into Bruce Banner.
For the duration of the movie, Bruce is unable to turn into the Hulk again.
Banner warns Doctor Strange and Tony Stark about Thanos moments before members of the Black Order arrive to take the time stone from Strange.
Strange is subdued and taken onto the Black Order ship.
Tony was going to propose marriage to Pepper Potts but he goes to space instead.
Peter Parker has spider sense now.
He used Ned to create a distraction on the bus, driven by Stan Lee, so he could sneak away and do superhero stuff.
And he gets his iron-spider suit.
Spider-Man joins Iron Man on the Black Order ship to save Strange.
The surviving member of the Black Order is defeated because Spider-Man once watched the "old movie" Alien.
Spider-Man, Iron Man, and Doctor Strange travel to Titan instead of returning to earth because Tony's ego believes they can stop Thanos.
They can't.
On Titan, they're joined by half of the Guardians of the Galaxy. They fight briefly before working together on a plan to stop Thanos.
Strange uses the time stone to see 14 million different future scenarios where they battle Thanos.
They lose each of them except one.
Thanos arrives and the fight begins.
They must prevent him from closing the fist with the infinity gauntlet.
Through their combined efforts they almost remove the gauntlet from Thanos' hand.
Until Star Lord learns Thanos killed Gamora and freaks out.
Star Lord ruins it for everyone and Thanos gets the upper hand.
Thanos stabs Iron Man through the chest and threatens to kill him if Strange does not forfeit the time stone.
Before the fight, Strange told Iron Man that he would let him or the kid (Spider-Man) die before giving up the time stone.
Now to save Iron Man, Strange gives up the stone as long as Thanos lets Tony live.
In possession of five of the six stones, Thanos transports himself to earth to get the final stone.
Strange tells Tony that it was the only way.

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When Thor, Rocket, and Groot arrive at Nidavellir, they discover the fires of the star are extinguished.
Peter Dinklage is a giant dwarf named Eitri, and he's the only living survivor of a visit from Thanos.
Thanos previously spared Eitri's life in exchange for forging a gauntlet capable of harnessing the power of the infinity stones.
However, after getting the infinity gauntlet, Thanos put out the forge's fire and encased Eitri's hands in metal.
To forge a new weapon capable of killing Thanos, Rocket and Thor must restart the fire and open the doors to reignite the forge.
Eitri creates an axe to replace Thor's hammer.
Stormbreaker can kill Thanos, and it has the power of the bifrost so Thor can transport himself anywhere in the nine realms.
Bad news, the axe needs a handle.
Good news, Groot donates a limb to provide the handle.
Thor takes hold of his new weapon and teleports himself, Rocket, and Groot to Earth.

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On Earth, the Secret Avengers (Captain America, Black Widow, and Falcon) rescue Wanda Maximoff and Vision from a Black Order ambush.
They meet up with War Machine and Banner at Avengers headquarters where General Ross orders their arrest for defying the Sokovia Accords.
Wanda is the only person powerful enough to destroy the mind stone and Vision asks her to do it to prevent Thanos from taking it.
Instead the group travels to Wakanda to see if the time stone can be removed without killing Vision.
In Wakanda, the Secret Avengers, War Machine, and Vision meet up with Black Panther and Bucky Barnes.
Hawkeye and Ant-Man are unable to be there because they took a plea deal after Civil War and are under house arrest.
Bucky gets his biomechanical arm back and everyone prepares for battle.
Wanda and Vision remain with Shuri in the Wakanda science and medical labs to remove the mind stone from Visions head.
The remaining members of the Black Order arrive with the armies loyal to Thanos.
The Earthbound Avengers and Wakanda's tribes war the alien hordes.
Since Banner can't Hulk out, he's using Tony's Hulkbuster armor.
To save their friends, Wanda and Vision join the fight instead of finishing the procedure to remove the mind stone.
The heroes are about to be overpowered by the invading enemies.
Then Thor arrives and zaps the aliens with lightning.
Rocket is impressed with Bucky's robotic arm and offers to buy it.
Just as the invading aliens are about to be defeated, Thanos arrives.
The team is out of time to thwart Thanos so Wanda is forced to destroy the mind stone that is still attached to Vision's head.
The process kills Vision but the stone is shattered preventing Thanos from possessing all six stones.
Unfortunately, Thanos has the time stone and he uses it to rewind time, restoring the mind stone and bringing Vision back to life.
Then Thanos rips the mind stone off Vision's head, killing Vision a second time.
Thor jumps in and impales Thanos through the chest.
Thanos tells him he should have aimed for the head.

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With all the stones in his possession, Thanos can achieve his goal of balancing the universe.
Thanos snaps his fingers and half of life in the universe dies. Those who pass dissolve into dust.
Thanos teleports to a new planet (perhaps a pocket universe inside the soul stone) and has a conversation with the childhood version of Gamora who asks if the cost was worth it.
He says it was.
Movie over. The villain wins. Roll credits.

Bucky Barnes dies.
Wanda Maximoff dies.
Black Panther dies.
Several members of Wakanda's army die.
Falcon dies.
Groot dies in front of Rocket Racoon.

On Titan, Doctor Strange dies.
Mantis dies.
Drax dies.
Star Lord dies.
Peter Parker dies. Because of his spider sense, he's the only one who can feel it coming. He collapses into Tony's arms crying "I don't want to go."

On earth, cars and planes and helicopters are crashing because the people controlling them perished.
Maria Hill and Nick Fury are in a car crashed caused by a pilotless vehicle.
Maria and Fury both die, but not before Fury sends a page to Carol Danvers, AKA Captain Marvel.