Avengers: Infinity War - 13 Major Plot Reveals From Trailer 2

7. The Guardians Return To Knowhere

It hasn't been officially revealed in the marketing yet, but we know that Benicio Del Toro's Collector has to return in Infinity War because he's still in possession of the Reality Stone (after the Warriors Three - RIP - stashed it with him at the end of Thor: The Dark World). And for the first time, the second trailer basically confirms that the Guardians (or some of them) return to Knowhere, presumably to check on the Stone after Thor reveals that he has it and that Thanos intends to steal it.

The shot confirming Knowhere is a brief one, but it shows one of the small mining craft from the first Guardians Of The Galaxy movie, so we know the location.

Rumour has it that Thanos will get there at the same time - or just after - the Guardians and gets his hands on the Collector first, and they'll be forced to pull off a heist to take the Stone from under his nose. After all, he doesn't have the Stone by the time he gets to Titan, so they presumably manage to thwart him.