In retrospect, the most unexpected of Marvel’s hits was all about the most unlikely of families. “Guardians of the Galaxy Vol. 3” emphasizes this point, with a rowdy and often emotional sequel that seems like a true finale, fuelled in no little part by writer-director James Gunn’s departure from rival DC.

Building franchises around lesser-known heroes has always been the most risky aspect of Marvel’s movie plans, making the success of “Guardians” in 2014 and its less-satisfying sequel a minor miracle. Look no further than the “Eternals,” another super-team that (while deserving of an asterisk due to the pandemic) did not fare as well.

The key to Gunn’s previous films was a combination of rich visual energy, distinct characters, ingeniously interwoven tunes, and a healthy dose of outright silliness. All of this is on full display in “Vol. 3,” along with a darker thread that dives heavily into the past of Rocket (voiced by Bradley Cooper), the freakishly clever and ruthless anthropomorphic raccoon, while also communicating an unexpectedly profound animal-rights message.

This installment of “Guardians” begins with Quill (Chris Pratt) becoming an emotional mess as a result of his estrangement from Gamora (Zoe Saldaa), who returned post-blip with no memory of their romance. He’s shocked out of his funk, though, by a threat that causes the team to spring into action to save one of their own, including a showdown with one of the more visually striking comics characters, Adam Warlock (Will Poulter), a creature with great strength but an almost infantile mind.