Captain Marvel chases after the Tesseract, the Guardians of the Galaxy glom an orb, Thor endeavours to capture Aether. These magical objects may seem homogeneous to MacGuffins, or simply plot contrivances that are denoted to keep the Marvel Cinematic Universe moving forward. But in fact, these objects are Infinity Stones: a group of gems that grant their owner great puissance. Thanos, a maleficence, purple alien, utilized that power to ravage half the universe in Avengers: Infinity War. Now, in the Infinity War sequel, Avengers: Endgame, it’s up to Marvel’s heroes to invert that damage, possibly by peregrinating through time and acquiring and eradicating all the Infinity Stones themselves afore Thanos can get his hands on them.
The Collector (Benicio Del Toro) inferred that the Infinity stones have been claimed by an ancient race known as Celestials. As the Celestials fell, the Infinity Stones were scattered all around the universe. The Power Stone was hidden in a temple at Morag and like that other stones were concealed while some were guarded by Masters of the Mystic Arts. The only question remained was: Who hid the Infinity Stones?
There are many hints and plot points which suggest that the Infinity Stones were hidden by an Earth-ling. The Reality stone was found by the Dark Elves of another realm, linked to Earth. The Time stone was designated to Masters of the Mystic Arts as Kamar-Taj and according to the Infinity war prelude comic, the masters also knew where the Power stone was concealed. This information gives way to the thought that Infinity Stones were in fact lost by Celestials on Earth.
The Eternals has been written (rewriting the original origin) as ancient aliens sent to protect Earth, most likely by the Celestials. Marvel Studio’s president Kevin Feige commented that “Eternals” spans tens and thousands of years- so, Eternals can, in fact, show us what happened to the Celestials and clear the remaining fog around the Infinity Stones. If this happens, Eternals becomes a smart prequel to the whole MCU set suggesting a story-line which is independent but still connects to the other movies of the franchise.