That would explain why Tony and Peter were with Quill on a planet that looked like a destroyed city, surely?
What it doesn't explain is Thanos being a central character. Because this implication would be a time-travelling romp with Tony/Peter/Whoever else but I can't see much room for Thanos but would also explain why there seems to be movies between Infinity War and the untitled sequel, because nothing 'major' or 'world ending' happens until [part 2].
I could see the first half being Thanos collecting the 4 stones not on Earth, getting to Earth and killing Vision for his Stone, and then the remainder being time traveling shenanigans
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[IMG]http://www.starmometer.com/wp-content/uploads/2017/02/Avengers-4.jpg[/IMG]
is that one of the mining ships in the back that everybody got in in Guardians 1 when Ronan came to Knowhere?