Is there an official source for the endgame plot?

The plot of Avengers: Endgame is detailed within the movie and in the official materials released by Marvel Studios, such as press kits and the film’s own credits. Wikipedia offers a concise summary of the story but is not an official source; it compiles information from various references rather than originating from the studio. For the most authoritative version of the storyline, consult the film or official Marvel publications. Wikipedia can still serve as a quick reference, but it should be cross‑checked against primary sources for accuracy.