Guardians of the Galaxy co-writer and director James Gunn has completed his story treatment for the sequel, well before shooting begins in early 2016. Gunn has long maintained that Peter Quill aka Star-Lord's (Chris Pratt) dad will figure into the plot - as foreshadowed near the end of the first movie - though a more recent comment by the filmmaker indicates there will be a daddy issues motif throughout Guardians of the Galaxy 2 in general.
Gunn has already said he'll be deviating from the Marvel comic book where it comes the identity of Star-Lord's father in Guardians of the Galaxy 2, though he also clarified that it's not going to be a big secret - "it's about what his [Peter's] relationship is to that character." Quill dealt with personal issues following the death of his mother in the first Guardians adventure, so it makes sense enough to explore his feelings about his father in the sequel... especially, now that Quill knows he's not a human.
Guardians of the Galaxy was also, to no small degree, about Peter, Gamora (Zoe Saldana), and the other Guardians coming together as a makeshift family - something the series will continue to be about, by the sound of it. Gunn teased as much in an interview with Vulture, without also spilling any beans about the sequel's plot beyond its basic thematic core.
"There's a lot of stuff I'm excited about in the new movie. Listen, I'm still excited about Star-Lord's character and where he goes. At its heart, Guardians is a story about families, and if the first film was about him and his mother, this is a story about fathers. So it's exciting to go there."
Gunn thereafter teased that he "knew for a long time" what Guardians of the Galaxy 2 would be about - and already has tentative plans for Guardians 3 (as he's also teased in the past), though for now all we can do is speculate about what the latter might entail. Either way, Yondu's (Michael Rooker) reference to Peter's dad near the end of Guardians was a pretty direct way of setting up that as one of the key plot threads for the sequel, and beyond.
Star-Lord won't be the only one with daddy issues in Guardians of the Galaxy 2, of course. Gamora and Nebula (Karen Gillan) - one of the Guardians villains returning for the sequel - still have issues with their own adoptive father, Thanos (Josh Brolin). Meanwhile, Drax the Destroyer (Dave Bautista) still remembers being a father, which is why he's also feeling wrathful towards the Mad Titan - being the boss of the recently deceased alien (Ronan) who murdered Drax's family.
Guardians of the Galaxy 2 will no doubt offer plenty of the quirk and humor that made the first installment a hit, but all the father drama could give the sequel as much heart (maybe more) than its predecessor had. Gunn may risk the ire of comic book fans by blazing a new trail, story-wise on Guardians 2, but overall he seems to be sticking to the same formula for success used on the first chapter - just with some different ingredients.
Captain America: Civil War will release on May 6, 2016, followed by Doctor Strange – November 4, 2016; Guardians of the Galaxy 2 – May 5, 2017; Spider-Man – July 7, 2017; Thor: Ragnarok – November 3, 2017; Black Panther – February 16, 2018; The Avengers: Infinity War Part 1 – May 4, 2018; Ant-Man and the Wasp – July 6, 2018; Captain Marvel – March 8, 2019; The Avengers: Infinity War Part 2 – May 3, 2019; Inhumans – July 12, 2019; and as-yet untitled Marvel movies on May 1, July 10 and November 6, 2020.