Brian Truitt

USA TODAY

Everybody’s favorite a-holes are back with a space adventure even bigger than their blockbuster debut.

In the 2014 breakout hit Guardians of the Galaxy, the motley crew of Marvel heroes led by roguish Peter Quill (Chris Pratt) saved the universe, and the sequel Guardians of the Galaxy Vol. 2 (in theaters May 5) opens with the rowdy bunch as cosmic rock stars. It’s art imitating life: Guardians came out of nowhere three years ago to make household names of talking raccoon Rocket (voiced by Bradley Cooper) and sentient tree Groot (Vin Diesel) — and rang up more than $333 million at the box office.

"The first movie was successful because we took chances and gave people the unexpected. This movie can only really be what it is, Guardians can only be what they are, if they’re taking a risk,” says writer/director James Gunn. “It means giving them a much different movie.”

With Vol. 2, the filmmaker promises bigger sci-fi concepts, new alien worlds to explore and some fresh personalities, including Peter’s long-lost dad: an ancient being known as Ego (Kurt Russell), who is in fact a living planet.

“Ego is the most powerful character I’m ever going to play,” Russell says. “I mean, he created himself! He’s the real deal.”

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Two months after the end of Guardians, Quill (aka Star-Lord) has taken responsibility for his wild bunch of intergalactic ex-convicts, who have to fight to stay a family as their leader comes to grips with finally finding his father. But “I don’t know if Quill is ever going to be a fully functioning, responsible adult," Pratt says.

Groot was "born" again as a baby after saving his friends in a climactic battle of the first film, and having a child around drives Quill and the muscular warrior Drax (Dave Bautista) crazy in the sequel, according to Gunn. The unlikely Guardians who take on parental roles for kid Groot are his slightly insane best friend Rocket and assassin Gamora (Zoe Saldana). “She’s surrounded by all these dudes who are so stupid half the time," Saldana says. "She has to be the voice of reason.”

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That carries over into Gamora's complicated relationship with her adopted sister, villainess killing machine Nebula (Karen Gillan). Another ne'er-do-well, Yondu (Michael Rooker) — the space outlaw who raised Quill — also returns and teams with Rocket and Groot when they run afoul of the Ravagers, while Drax makes a new friend in Ego's confidante Mantis (Pom Klementieff). "He looks like this big tough brute but there's a sense of innocence and heartbreak about him," Bautista says of his green-skinned powerhouse.

While Guardians worked on improving its own superhero game, Saldana noticed how much the successful first film has inspired subsequent comic-book films such as Deadpool and Suicide Squad.

“It’s given permission to so many other filmmakers to let these action movies not only have a little more heart and soul but to have a little more entertainment besides just, ‘CRASH! BOOM! BANG! BLARGH!’ ” Saldana says. “It makes me really happy.”