Missouri is a state located on the midwestern region of the United States of America.
Captain America Comic
Gary Hendricks, a young fan of the war hero Captain America, received a copy of a comic book edited to help boost morale during World War II, that told an action-packed story about his favorite Star-Spangled Hero.
Hendricks avidly read the story where Captain America stopped a group of military traitors from stealing a newly-created bulletproof Electro Suit. Captain America, triumphant, swore that he would ever be vigilant and protective of the nation's freedom.
Hendricks finished reading the comic, and entered his home to have dinner. The mailman left Hendrick's mail near the comic, as he knew that he would be back to retrieve it.
In the late 1970s and early 1980s, Ego took on a human form and visited Missouri on Earth a total of 3 times, in order to plant one of his seeds to include Earth in his "expansion" plan. During this period, he fell in love with Meredith Quill and impregnated her. However, because of the fact that his planet would perish if he leaves it too long, and because he felt Quill was becoming a major distraction to his plan, he planted a tumor in the back of her head and permanently left. Meredith would eventually give birth to Peter Quill following this.
In 1988, Peter Quill went to the hospital where his mother, Meredith had been admitted suffering from terminal cancer caused by the tumor Ego planted in the back of her head. He sat in the waiting room of the hospital, while his grandfather and the rest of his family spent their last moments with Meredith.
Peter listened to his "Awesome Mix" tape on his Walkman until his grandfather came over to him, telling him that his mother wanted to speak with him. He took Peter's headphones off of his head and put the Walkman inside his backpack.
Peter entered the room, where Meredith was lying sick in a bed. Meredith noticed that Peter's eye was bruised and asked him why had he been fighting with other boys. Peter shrugged his shoulders, but then admitted that he confronted the other boys for killing an innocent frog.
Meredith compared Peter to his father, whom she described as an angel composed of pure light. Meredith's eyes closed for a moment, so her father called her out loud to avoid that she lost consciousness, and reminded her that she had a present for Peter. Meredith handed his son the gift and a letter, and his grandfather put them in the backpack.
Meredith told Peter to open the letter and the gift when she was gone, and Peter started to cry. Meredith promised his son that his grandfather would take care of him until his father came back to retrieve him, and asked Peter to take her hand.
Peter looked away crying, and despite his grandfather prompted him to take Meredith's hand, Meredith's heart stopped before he took her hand. Peter called to his mother, and as Doctor Fitzgibbon rushed into the room, Peter's grandfather carried Peter out and asked him to stay outside.
Peter watched how his grandfather walked back into the room, and then he ran outside the hospital, falling to his knees as he continued crying. Suddenly, a spaceship appeared on the sky above Quill, and its occupants abducted him, taking him out of Earth upon his father's request.
Keeping the Bartons off S.H.I.E.L.D.'s Files
When Clint Barton was recruited into S.H.I.E.L.D., Nick Fury made sure his family's existence would be a secret, setting up a farmhouse as a secure, isolated place in Missouri where they could live in safety.
Investigation of the Mandarin Attacks
Tony Stark started investigating the Mandarin, in order to enact revenge for the explosion that almost killed Happy Hogan. As usual, the explosive device was not found, but the heat from the blast was particularly high, more than 3000 degrees Celsius.
Stark studied the different thermogenic occurrences to study other cases based on the particular temperature of the explosion, discarding the thermogenic signature at Springfield for not being as high as that of the explosion.
In 2014, as the Battle on Ego's Planet took place in a separate part of the universe, the seed previously planted by Ego erupted into a blue blob and began to devour Missouri, with the intention of eventually eating up all of Earth. Many civilians, despite attempts to flee, were swallowed up and killed. Eventually, thanks to the efforts of Peter Quill and the Guardians of the Galaxy from Ego's planet, the seed stopped devouring the area and eventually perished along with Ego.
In 2015, Clint Barton took the Avengers to his homestead, revealed to be the house where he lived with his family. While there, Tony Stark and Steve Rogers discussed the future of the team. Later on, Nick Fury visited them there to discuss the ongoing events, and how the Avengers needed to act to achieve victory. After the battle, Barton retired from the Avengers and returned to Missouri to live with his family, now with a new member of the family.
A Trap for S.H.I.E.L.D.
In 2017, S.H.I.E.L.D. infiltrated the St. Louis Aerospace Facility after receiving an unidentified signal from the area. There they found Agent Piper, who told them that she had struck a deal with General Hale for the Kree Orb following the disappearance of her colleagues and the listing of S.H.I.E.L.D. as a terrorist organization.
Piper would activate the Kree Orb from time to time, knowing that if her colleagues saw the beam of light emitted from it, they would likely investigate. The beams of light were then spotted by the Chronicom Noah, who had been monitoring the St. Louis Aerospace Facility from the Lighthouse.
However, it turned out to be a trap for S.H.I.E.L.D.. Piper revealed that she had been arrested and had to agreed to bring her colleagues to Hale, but she was told that no harm would come to them. At this moment, a team of Sleeper Mechs led by Ruby Hale arrived at the facility.
A fight between S.H.I.E.L.D. and the Sleeper Mechs broke out, which resulted in Ruby slicing off Yo-Yo Rodriguez' arms. This forced S.H.I.E.L.D. to flee the St. Louis Aerospace Facility with Piper and the Kree Orb.
In 2018, Clint Barton, Laura Barton, Lila Barton, Cooper Barton, and Nathaniel Barton were outside close to their home. Laura prepared lunch for a picnic, while Cooper and Nathaniel played catch and Clint and Lila did archery. After Laura called the family in for lunch, the Snap happened and she and the children disintegrated, leaving Clint alone.