When we last saw the staff of Planet Express, in 2009's direct-to-DVD movie Into the Wild Green Yonder, they were fugitives aiming their ship toward a wormhole, their fates unknown -- clearly reflecting the uncertainties surrounding Futurama at the time.

But more than a year since that nebulous ending, and more than seven since Fox canceled the original series, Futurama returned this week for its sixth season -- the four movies count as the fifth -- with "Rebirth," an episode that picks up where Yonder left off, and effectively hits the reset button.

We learn that the Planet Express ship, with Zapp Brannigan's Nimbus in hot pursuit, passed harmlessly through the Panama Wormhole to Earth -- it's Earth's central channel for shipping -- only for both vessels to crash in a fiery heap outside of the company's headquarters. Professor Farnsworth survives and uses a vat of human stem cells to regenerate the bodies of his dead employees. (Don't worry, they're not embryonic stem cells. They're "harvested from perfectly healthy adults -- whom I killed for their stem cells.")

The rebirths don't go according to plans, of course: With Bender's energy rapidly fading, the Professor fits him with a doomsday device as a power source. The hitch is that it generates too much energy, requiring Bender to constantly party to prevent him from exploding and killing everyone. It's a funny enough premise that very quickly grows old as it turns into a rehash of 10-year-old "hard-living Bender" gags.

Leela, too, runs into a snag, as the Professor can't revive her body once it emerges from the pink goo: "Somethings' wrong! She's not responding to my poking stick!" That, naturally(?), leads a despondent Fry to build a robot version of the woman he loves, transforming the episode from a reintroduction of the characters into an examination of the relationship between Fry and Leela. And that's not necessarily a good thing, considering their dynamic works best when Fry is pining for Leela and the audience is left wondering whether she'll return his affections.

Fortunately, "In-A-Gadda-Da-Leela" is stronger, in no small part because it's a Zapp Brannigan episode. Those seldom, if ever, fall short of expectations.

But this isn't just a Zapp Brannigan episode; it's a Zapp Brannigan episode littered with sexual innuendo, from the ad slogan in Zapp's '50s B-movie serial dream -- "I wax my rocket every day" -- to the Star Trek: The Motion Picture-inspired mysterious death sphere called "V-GINY" to juvenile, yet funny, lines like "Firing pocket rocket!"

"In-A-Gadda-Da-Leela" is a return to classic form, with Zapp and Leela flying a one-man stealth fighter -- Leela has to sit on Zapp's lap -- to destroy the death sphere heading toward Earth. Before they can accomplish their mission, their craft crashes on what appears to a tropical planet, leaving them (apparently) the only surviving humans. That's right, they're the new, and nude, Adam and Eve in the Garden of Eden. At least that's what Zapp would like Leela to believe.

I felt let down by "Rebirth," which is perhaps inevitable; I had high expectations for the show's return. But with "In-A-Gadda-Da-Leela," it feels like Futurama is truly back, and just as good as it ever was.

Scattered thoughts

• Bender's pre-opening voiceover for "Rebirth": "On the count of three, you will awaken refreshed, as if Futurama had never been canceled by idiots and brought back by even bigger idiots"

• Fry: "Why does everything I date run away?"

• "Glove recognized. Proceed, Mrs. Eisenhower."

• "In-A-Gadda-Da-Leela" contained several references to Star Wars and Star Trek, of course, but my favorite was the use of the Janeway's Guide to attempt to identify the death sphere (a nod, too, to Jane's Aircraft Recognition Guide).