Synopsis

In the opening scene on planet Earth in the year 1988, young Peter Quill sits in the waiting room of a hospital, listening to the Awesome Mix tape no. 1 on his walkman as his grandpa (Greg Henry) comes out and gets him so he can say goodbye to his mom who is dying from cancer. His dying mom gives him a present and tells him his father was an angel and that Peter is just like him. She asks for his hand, but he's too scared to take it. Just then, she dies. The distraught Peter runs outside and is abducted by a spaceship.

26 years later on the planet Morag, an adult Peter Quill A.K.A. The Star-lord (Chris Pratt) is searching for a mysterious Orb. He finds it as Korath (Djimon Hounsou) and his henchmen find Peter. After a shootout, Quill escapes and returns to his ship, Milano.

His partner/mentor Yondu (Michael Rooker) calls and tells him to give him the Orb. Quill decides he's going to sell it on his own.

On the Kree Warship, the Dark Aster, Korath reports to Ronan (Lee Pace) that he failed in getting the Orb and that it's in the hands of Quill. Ronan sends assassin Nebula (Karen Gillan) after him, but before she can go, Gamora (Zoe Saldana) volunteers instead.

On the planet Xandar, Quill takes the Orb to a buyer and asks what it is because Ronan's goons were after it too. The buyer suddenly doesn't want anything to do with it and kicks Peter out of his shop. Outside, Gamora jumps Peter and tries to retrieve the Orb herself. Nearby, Rocket Raccoon (voice of Bradley Cooper) and Groot (Vin Diesel) see there's a bounty on Quill's head, so they join in the fight. Its not too long before they're all arrested by Nova HQ and sent to a space prison called The Kyln. (Note: Stan Lee has a cameo appearance as an old man on Xandar, chatting up with a young lady - Rocket calls him a pervert)

Pretty much everyone in prison wants to kill Gamora because she's the daughter of Thanos. Drax the Destroyer (Dave Bautista) has a personal vendetta against her because Ronan killed his wife and daughter, so he wants to avenge them by taking the life of one of his family members in return. Gamora explains that shes also against Ronan and was planning on double crossing him. Quill steps in and helps argue in Gamora's favor.

At Sanctuary, Ronan reports to Thanos (Josh Brolin) that Gamora is a traitor. Thanos tells him to take care of her and get the Orb. He also notes that Gamora is his favorite daughter, which pisses of Nebula (his other daughter).

Gamora has a plan to sell the Orb to someone else. Quill, Rocket and Groot agree to help and split the reward. Rocket has a plan to escape the prison. He needs one of the guards wrist devices, a prisoners prosthetic leg and a battery from a tall column in the prison. As he explains that its very important to take the battery last, Groot grabs it first. The alarms go off and security droids fly in. Gamora goes to get a wrist device as Quill negotiates the prisoners leg. Drax decides to join in the escape too realizing that eventually Ronan will go after Gamora and then he can kill Ronan himself.

Everyone gets the stuff they need and make it to a guard station near the top of the prison. Rocket is surprised that Quill actually got the leg and says he didn't really need it. It was a joke. Rocket rigs up the stuff to turn off the gravity in the prison and to use the security droids as jets to fly the guard station out of the prison. They escape, but Quill goes back and gets his walkman from one of the guards.

Yondu goes to his broker and finds out Quill still has the Orb.

Everyone on Quills ship gets to know one another better. They don't like each other at all. Soon they arrive at Knowhere (corpse of an unknown being) to meet with the Collector. While they wait for their appointment, Drax, Rocket and Groot get drunk and gamble. Gamora and Quill bond over music. He explains that his mom made him the mix tape of her favorite songs. She listens and likes it. He asks her to dance, but she doesn't. He says it reminds him of an old fable about other people who didn't dance. It was called Footloose. He makes a pass at her, but she says shes not one of the doe eyed girls hes used to and she wont fall for his pelvic sorcery.

Before they can meet with the Collector, Drax, Rocket and Groot (all drunk) get into a big fight. Drax thinks Groot is dumb and Rocket is tired of people calling him a rodent. The Collector's assistant fetches them and they all go to meet him. Drax goes off on his own and makes a call.

The Collector (Benicio Del Toro) opens up the Orb to reveal and Infinity Stone. He explains that its an all-powerful thing. There are more of them and they can destroy planets. His assistant is fed up with him and grabs the stone to destroy him. She and everything in the area blows up (you can see Cosmo the Soviet space dog running away). Everyone manages to escape, with the Infinity Stone. They decide the safest place to take it is Nova Headquarters. Its too dangerous to be anywhere else.

Suddenly the group is ambushed by Ronan and his crew. That's the call Drax made. He was tired of waiting to face Ronan. Yondu shows up too. Gamora, Rocket and Quill take off in little mining ships while Nebula and some goons chase after them. Drax tries to fight Ronan, but gets his ass handed to him. Ronan says he doesn't even remember killing his family, nor will he remember killing Drax.

Nebula chases Gamora's ship above the atmosphere and blows it up. She gets the Infinity Stone and leaves Gamora floating in space to die. Quill calls Yondu to tell him where he is, then exits his ship, and gives Gamora his mask to keep her alive.

Yondu abducts Quill and Gamora right before they die. This is where we see that its the same ship that abducted Quill as a child.

Onboard the Dark Aster, Ronan tells Thanos that he decided to cut him out of the deal and will destroy Xandar himself and then go after Thanos. He puts the Infinity Stone into his hammer.

Yondu is going to kill Quill for double crossing him, but doesn't when Quill says that he has a plan to get the Orb back. Meanwhile on Knowhere Drax, Groot and Rocket decide to join forces and save Quill and Gamora from Yondu. They fly Milano to Yondu's ship and threaten to blow it up with a special weapon Rocket built unless they release Quill and Gamora, but Quill stops them. On board the Milano, the Guardians asks if he really has a plan or was lying. He says he has the part of a plan (12%). Everyone scoffs. Rocket says that they will most likely die if they try to stop Ronan. Quill points out that they've already lost so much, that at this point they have nothing to lose.

Quill warns Nova HQ on Xandar that Ronan is coming to destroy them and they should get ready. Rocket is going to blow a hole in Ronan's ship so Quill, Groot, Drax and Gamora can board it. Gamora is going to cut the power for Ronan's security and then they're going to blow him up with a cannon that Rocket made.

They start the plan. Rocket blows a hole in the Dark Aster and then helps Yondu and his men defend Xandar against Ronan's fighter ships. Yondu is shot down and uses his arrow weapon to take out an entire platoon of goons.

On the Dark Aster, Gamora and Nebula get into a big fight, while Drax, Quill and Groot go to the bridge of the ship.

The Nova ships form a giant net and slow the descent of the Dark Aster. Gamora finally beats Nebula, who falls, landing on a Ravager ship and commandeers it, throwing the Ravager out the window and flying away. Ronan orders his ships to kamikaze into Xandar. Rocket and Yondu's men shoot as many of the ships down as they can.

Almost to the bridge, Drax kills Korrath. Groot makes impales a bunch of goons and whips them around taking out even more. Everyone makes it to the bridge to fight Ronan. Again, he's too strong for them, but Quill manages to shoot him with Rocket's super cannon. It does nothing. Rocket crashes the Milano into the bridge and seems to have destroyed Ronan. The entire ship is plummeting towards Xandar, so Groot forms a giant nest around the Guardians for safety. Rocket is upset because he knows what Groot is doing will end up killing him. Groot, who up to this point has only said, "I Am Groot" responds with, "We are Groot".

The ship crashes. Everyone except Groot is okay. Groot is a pile of twigs strewn all about. Its not over though, because Ronan is still fine. He sarcastically calls Quill and his crew the Guardians of the Galaxy. As he raises his hammer for a final blow, Quill stands up and starts to dance to the song "Ooh-ooh Child". Ronan asks what he's doing, he responds, "distracting you" as Drax and Rocket shoot Ronan's hammer, releasing the Infinity Stone. Quill grabs the Infinity Stone before Ronan. It's going to kill him, but Gamora tells him to take her hand. He flashes back to when he didn't have the courage to take his mom's hand, and he grabs Gamora's. Drax and Rocket grab him too and the power from it is spread among the four of them. They kill Ronan.

Yondu shows up and demands the Stone as per his original deal with Quill. Quill hands him the Orb. As Yondu and his men take off, one of them notes that he likes Quill and they're glad they didn't take him back to his dad like they were supposed to all those years ago.

Gamora is upset that Quill gave up the stone, but he reveals that he switched the Orbs.

At Nova HQ, Quill learns he's only half human and half something ancient and unknown.

There is a party on Yondu's ship. His crew is celebrating but Yondu looks suspiciously at the Orb and then decides to open it. In it is a troll doll. He smiles.

Quill finally opens the present his mom gave him as a kid. It's a Awesome Mix tape no. 2. He asks the Guardians where they want to go. Gamora says, "You lead, Starlord". He asks if they want something good or something bad then decides on both. Rocket holds a tiny Groot planted in a pot.

End Credits

During the credits, a little bit larger version of Groot dances in the pot to Quill's 1980s music, but stops when Drax looks at him.

After the credits...The Collector is sitting on the wreckage, drinking when Cosmo comes up and licks his face. We hear the voice that says it's disgusting. Camera turns and reveals Howard the Duck sitting on a broken cage, drinking as well.