“GUARDIANS OF THE GALAXY VOL. 2” — 3½ stars — Chris Pratt, Zoe Saldana, Dave Bautista, voices of Bradley Cooper and Vin Diesel; PG-13 (sequences of sci-fi action and violence, language and brief suggestive content); in general release

2014’s “Guardians of the Galaxy” got the band together, and now “Guardians of the Galaxy Vol. 2” is ready to send them out on tour. The summer 2017 movie season has officially arrived.

After a quick flashback prologue, we find the group in an off-the-wall opening credits scene, battling a massive multi-tentacled space monster while Baby Groot — a scene-stealing infant version of 2014’s towering Ent creature, still voiced by Vin Diesel — dances to Electric Light Orchestra's “Mr. Blue Sky.”

The whole band is back — the alien muscle-bound literalist Drax (Dave Bautista); green-skinned super assassin Gamora (Zoe Saldana); Rocket (voiced by Bradley Cooper), the raccoon-shaped science experiment with anger issues; and Peter Quill, aka Star-Lord (Chris Pratt), the scavenger-turned-noble leader who has been traveling the universe ever since getting abducted from Earth as a young boy.

Before the dust can settle from their opening battle, the Guardians are on the run from an elitist race of gold-colored aliens called the Sovereign who are angry that Rocket stole some of their batteries. But just as the Sovereign are closing in, the Guardians are saved by a mysterious man in an egg-shaped spaceship.

The mystery man is Ego (a silver-haired Kurt Russell), a powerful demigod who also happens to be Star-Lord’s long-lost father. Ego has his very own planet — in fact, the way he describes it, he is the planet — and he’s eager to help his son fulfill his divine destiny.

In the meantime, some familiar faces from the first movie are back to cause trouble. Yondu (Michael Rooker) has been hunting the Guardians ever since Star-Lord and company duped him out of one of an Infinity Stone, and Nebula (Karen Gillan) is back with her various bionic parts to hunt down her half-sister Gomora (who is still trying to reconcile her budding romance with Star-Lord).

It takes a while for “Vol. 2” to get its legs, but once it kicks into gear, fans can expect the same mix of outrageous CGI-action and irreverent humor that made the first film so fun. Most all of the Marvel films harbor a wry, fan-friendly sense of humor, but the “Guardians” series has a voice all its own, refusing to let a touching moment go by without injecting some kind of absurd one-liner.

The first film was also defined by its soundtrack, and “Vol. 2” — named in tribute to Star-Lord’s various classic rock mix tapes — keeps that ball rolling. Fans will enjoy scenes set to Fleetwood Mac, Cat Stevens and Sam Cooke tracks, and returning director James Gunn deserves some kind of award for what he does with Looking Glass’ “Brandy (You’re a Fine Girl).”

And yet, “Vol. 2’s” greatest accomplishment may still be its effective way of developing its myriad characters. Aside from Ego and his female/insect assistant Mantis (Pom Klementieff), “Vol. 2” is pretty much playing with the same deck of characters we got to know in the first film, and the additional time spent with the Guardians (as well as Yondu and Nebula) makes everyone more endearing.

Both hard-core comic fans and more casual movie fans will be happy with the results, though parents may cringe to find “Vol. 2” a bit more crude and violent than the first film. Rest assured that any kid who does see it — and probably a few adults — will want a Baby Groot toy.

Audiences will also want to hang around through the credits for multiple bonus scenes — some played for laughs, and others that hint more strongly at the Guardians’ future adventures in the Marvel Cinematic Universe. For most, those future adventures can’t come soon enough.

“Guardians of the Galaxy Vol. 2” is rated PG-13 for sequences of sci-fi action and violence, language and brief suggestive content; running time: 136 minutes.