I had a thought of a future Marvel film, maybe part of a final phase(after phase three in the Marvel Cinematic Universe) which would crossover The Avengers, Guardians of the Galaxy and Agents of S.H.I.E.L.D. and involve the Infinity Stones.
Before I explain the film idea, let's first talk about the Infinity Stones. First detailing the ones we know so far;
The Tesseract - Also known as the Cosmic Cube in the mainstream comics, and shown in end-credit scene in Thor, and fully shown in Captain America: The First Avenger and The Avengers. The Tesseract was originally Asgard property, until after the war with the Frost Giants Odin gave the Tesseract to the humans, as compensation for the great loss during the war. The Tesserect was kept hidden many centuries by those who still hold on faith in Norse mythology until it was taken by HYDRA led by the Red Skull and used as a weapon. The Tesserect possess the ability of teleportation(taking whoever wields it whereever in space they want), but if intensified like how HYDRA did with it, it can disintegrate living matter. After the war though, and retrieved by Howard Stark, the Tesserect was studied by Stark(before handing it over to the now-formed S.H.I.E.L.D.) and used it as a template to create a polluting-free energy known as the Ark Reactor(which not only saved his son Tony Stark's life but used to power the Iron Man suits). But when Loki tried to use the Tesseract's power to open up a portal for the Chitauri to invade, the Avengers quickly prevented it and Thor took the cube(along with his brother) to Asgard.
The Aether - The Aether was shown in Thor: The Dark World, it was used by the Dark Elves to try to revert the universe back into its earlier state(by destroying reality itself). But the Asgardians prevented it and it hid the Aether where no one could find it. Unfortunatley, Jane Foster inadvertently found it while investigating temoral shifts through space, thus triggering the Dark Elves search for it. The Aether appears as a dark, red, viscous liquid that can float in the air. The Aether acts like a symbiotic force that is capable of being absorbed into the body of a living host, granting that person immense strength, power, and seemingly unlimited capabilities. The Aither was eventually reclaimed after Thor defeated the Dark Elves, but was handed over to the Collector instead as the Asgardians couldn't risk what would happen if putting to Infinity Stones in the same room(or even area) together as they have the Tesseract in their vault.
The Power Orb - The Power Orb was shown in Guardians of the Galaxy. The Power Orb actually a glowing purple gem inside a protective housing sphere. The Power Orb is an incredibly unstable power source which, when used a full potential, has enough power to obliterate an entire planet. Peter Quill(AKA Star Lord) Found the Power Orb and was intending to sell it. But after some minor circumstances(he, Gamora, Rocket & Groot got arrested), they all managed to escape(accompanied by Drax who seeks revenge on Ronan the Accuser). The five tried to sell it to the Collector but another (two)mishaps causes the orb to be taken by Ronan and plans to use it to destroy the home world Xandar. But he was eventually defeated by the now-formed Guardians of the Galaxy and the Power Orb kept in safe keeping by the Nova Corps.
So far, those are the Inifity Stones. And here are what I think the last three stones are and can do;
The Fountain - A small, pyramid shaped stone that release never ending mist when used. The Fountain is supposedly the fabled Fountain of Youth. It also has the 'lazarus effect', which means it has the power of life itself, and can do simple things like heal injury or sickness, but can do great feats like saving someone from a terminal illness or near death. It can also(as the name implies) restore the person's youth, and can even bring back the dead.
The Eye - One of the most simplest stones, the Eye(despite the name) is a large glowing blue gem. As the names imples, it has the power of 'awarness of the universe' meaning it allows whoever holds it to see whatever they want, whereever they want, no matter how far. It most likely rivals that of Heimdall's ability.
The Excalibur - The actual sword of the Arthurian legend, the sword Excalibur is actually an Infinity Stone, that fell to earth in the middle-ages where Merlin had found it and had it crafted and forged into a sword fit for king Arthur. What it can actually do is having the power over the basic elements, which some people in those days mistook it for magic.
And now the plot for this film. It might end up as a two-parter perhaps with an ensemble cast, but the plotline would be that Thanos gives the people of Earth a message; hand over the remaining Infinity Stones, or die(implying that we will come to earth with an armada, believing the remaining Infinity Stones are on earth). And so, a race is on for the Avengers as they search around the world searching for the Infinity Stones, but end up facing various villains. It would also crossover with Guardians of the Galaxy and Agents of S.H.I.E.L.D. where everyone unite to fight Thanos and his vast Chitauri army, while reluctantly teaming up with most of the villains.
Casts: Robert Downey Jr(Tony Stark/Iron Man), Chris Evans(Steve Rogers/Captain America), Chris Hemsworth(Thor), Mark Ruffalo(Bruce Banner/The Incredible Hulk), Scarlett Johansson(Natashas Romanova/Black Widow), Jeremy Renner(Clint Barton/Hawkeye), Aaron Taylor-Johnson(Pietro Maximoff/Quicksilver), Elizabeth Olsen(Wanda Maximoff/Scarlet Witch), Ian McKellen(Eric Lensherr/Magnito), Clark Gregg(Phil Coulson), J. August Richards(Mike Peterson/Deathlok), Don Chealde(James Rhodes/War Machine/Iron Patriot), Gwyneth Paltrow(Pepper Pots), Natalie Portman(Jane Foster), Jaime Alexander(Lady Sif), Anthony Mackie(Sam Wilson/Falcon) Chris Pratt(Peter Quill/Star Lord), Zoe Saldana(Gamora), Dave Bautista(Drax the Destroyer), Bradley Cooper(Rocket) Vin Diesel(Groot), Benicio Del Toro(The Collector) Anthony Hopkins(Odin), Tom Hiddleston(Loki), Hugo Weaving(Johann Schmidt/Dell Rusk/Red Skull), Mickey Rourke(Ivan Vanko), Shaun Toub(Ho Yinsen/The Mandarin), Jai Courtney(Skurge the Exacutioner), Natalie Dormer(Amora the Enchantress), Thomas Kretschmann(Baron Strucker), Svetlana Khodchenkova(Viper/Madame Hydra), Liev Shreiber(Victor Creed/Sabretooth), Hugh Jackman(Logan/Wolverine), Patrick Stewart(Charles Xavier/Professor X) Paul Bettany(The Vision, J.A.R.V.I.S.), Samuel L. Jackson(Nick Fury), Cobie Smulders(Maria Hill), Andrew Garfield(Peter Parker/Spiderman) Rhys Ifans(Curt Conners/The Lizard), Dane DeHaan(Harry Osborn/Green Goblin), Felicia Jones(Felicia Hardy/Black Cat), Manu Bennett(Emil Blonsky/Abomination), Josh Hutcherson(Rick Jones), Paul Rudd(Scott Lang/Ant-Man), Michael Douglas(Hank Pym), Sebastian Stan(Bucky Barne/Winter Soldier), Stanley Tucci(J. Jonah Jameson), Josh Broslin(Thanos).
That's roughly what I think this film would be. I'm assuming there they'll be a final phace, after Phase three, with a few more other films(One of them being Iron Man finally meets the REAL Mandarin, another one where Thor faces the Wrecking Crew but teams up with an alien named Beta Ray Bill, another with Hulk in his own film, and Captain America meets the return of Red Skull). But I think this would be the last Marvel.
Tell me what you think?