The Supreme Kree Intelligence manipulates Captain Marvel and Rick Jones into a war on the Null-Tron planet. But that’s not important. This story matters because it tells us that there are six soul gems, each with a different power, and that Adam Warlock has one. This is the first time there’s the concept of infinity stones.
It ends with Mar-Vell and Jones deciding to return to Earth.
Note: Issue #45 is part of the Marvel Bi-Centennial celebration (for the year 1776), but other than the fact that it says it’s a “bicentennial” story in the title, there’s nothing really here about that.