Chronologically issue 5 of Giant-Size Defenders (Marvel, 1974 series) occurs before this issue. On sale date from the Comic Reader #118.
This issue has variants:
The Defenders [Valkyrie; Nighthawk [Kyle Richmond]; Dr. Strange [Stephen Strange]; Hulk [Bruce Banner]]; Jack Norriss; Aragorn; Guardians of the Galaxy [Charlie-27; Martinex; Vance Astro; Yondu]; Vance Astrovik; Killraven (in flashback); Badoon; Captain America (in flashback); Thing (in flashback); Killraven (Cameo)
Synopsis
The Defenders travel to the future while helping the Guardians of the Galaxy return to their time. Retelling of the events between the current time and the future of the Guardians of the Galaxy.