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Star Trek: Discovery season 4: trailer, cast, plot and what we know so far

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Spooling up the spore drive for Star Trek: Discovery season 4. (Image credit: CBS All Access/Netflix)

The best instalments of Star Trek are often defined by their villains: notably a vengeful, genetically enhanced superman in The Wrath of Khan; the warmongering Klingons; and those cybernetic enemies of individuality, the Borg. In Star Trek: Discovery season 4, however, the antagonist will be… a gravitational anomaly?

Now settled in the distant future of the 32nd century, the crew of the USS Discovery have defeated the criminal empire of the Emerald Chain, and solved the mystery of the “Burn” that had made warp travel impossible. With Michael Burnham (Sonequa Martin-Green) now in the captain’s chair – the ship’s fourth commanding officer in as many years – restoring the Federation to its former glories will be the order of the day. In fact, with Burnham saying in the trailer that, “We are not in this alone,” it looks like it’s going to take a massive act of co-operation to deal with an anomaly five light years across.

It’s now been confirmed that Star Trek: Discovery season 4 will warp its way onto Paramount Plus in late 2021. As production comes to an end, we’ve explored the Federation databanks to find out everything you need to know about the latest instalment of Trek’s current flagship TV show – everything from casting and the first trailer, to the burning questions Star Trek: Discovery season 4 needs to answer.

Star Trek: Discovery season 4 release date: when we expect it

Star Trek: Discovery season 4 has a release date of late 2021, it's been confirmed as of April 5 2021 (aka First Contact Day). The show will release on Paramount Plus this time, the rebranded version of CBS All Access.

The previous season had barely even started airing when Star Trek: Discovery season 4 got the official greenlight on October 16, 2020. Two weeks later, on November 2, production got underway at the show’s Toronto base, and is set to continue until June 2021. Inevitably, Covid-19 restrictions will be a major factor in the shoot, and – as dictated by Canadian rules – the cast had to isolate for two weeks before coming to set.

Coronavirus restrictions prompted the production team to put together a pipeline for working remotely on a third season that wrapped days before North American lockdowns kicked in. 

Composer Jeff Russo sent microphones to the members of his orchestra so they could record individually; actors received motion capture equipment so they could complete their performances in homemade studios; and editors and effects artists worked remotely. “Our editors, miraculously and heroically, took their editing bays into their living rooms,” Alex Kurtzman, executive producer and overseer of Star Trek’s current raft of TV shows, told IndieWire. “We also scored the entire season, mixed the entire season, color-timed the entire season, all from [a] laptop.”

Reports suggest the process was further refined on Star Trek: Discovery season 4,  with reports from revealing that the show will make use of the groundbreaking augmented reality LED screens pioneered by The Mandalorian. Suddenly the fact that travel for location filming was off the table didn't seem quite so much of a problem…

Despite news in Deadline that a positive Covid-19 test had caused production to temporarily shutdown in April 2021, subsequent reports (including a May tweet from writer Olatunde Osunsanmi, which announced that the finale episode’s shot list was complete) suggested that Star Trek: Discovery season 4 was on track to wrap in June – though we're still waiting on official confirmation.

Cut to the chase

  • What is it? The fourth season of Star Trek: Discovery, the sixth live-action TV series based in the future Gene Roddenberry created back in the 1960s.
  • Where can I watch it? Star Trek: Discovery season 4 will be available on Paramount Plus which used to be called CBS Access. In other territories, it should be available on Netflix.
  • When can I watch it? While don't yet have an exact stardate, Paramount has confirmed the show beam onto your TV before the end of 2021.

Star Trek: Discovery season 4 trailer: see the first teaser here

See more

Yes, there's a first teaser trailer for Star Trek: Discovery season 4, that was unveiled at the First Contact Day virtual event – watch it above.

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Expect Cleveland Booker (David Ajala) to be a major player in Star Trek: Discovery season 4. (Image credit: CBS All Access/Netflix)

Star Trek: Discovery season 4 cast: who do we expect to return?

It’s a case of ‘as you were’, with most of the established cast returning for another tour of duty – presumably they’re excited to be wearing new-look, Trek-standard primary-colored uniforms that don’t look quite so much like tracksuits.

It goes without saying that Sonequa Martin-Green is back as Captain Michael Burnham, and even though her predecessor in the big chair, Saru, has relocated to his home planet of Kaminar, Doug Jones still has a part to play. “It felt important for all of our characters to find new layers for them, to find new place for them to go, new things for our actors to play, and new ways for the characters to go,” showrunner Michelle Paradise told TVInsider. “[In season 3 we highlighted] that Saru hasn’t had a huge connection to Kaminar since leaving, and in a season that is all about connection – family connection and cultural connection – it seemed like an organic place to explore that theme with him.”

Among the lead cast, Anthony Rapp and Wilson Cruz reprise their roles as Lt Cmdr Paul Stamets and Dr Hugh Culber, while season 3 standout David Ajala is back as the 32nd century’s most famous cat owner, Cleveland ‘Book’ Booker. (Sadly, a Grudge the Cat spin-off is yet to be announced.) And surely Mary Wiseman’s Sylvia Tilly will be looking to make the First Officer role her own.

“[Saru] sees strength in [Tilly] she doesn’t quite see in herself necessarily,” Paradise said in TVInsider. “Then, [we watched] her over the course of the season become more confident in herself to the place where she’s ultimately able to serve as Number One, and having to essentially be acting captain in this crisis situation, where she handles herself beautifully. What does that mean to come is, I’m sure, a question she’ll be asking herself and we’ll be exploring in Season 4.”

The supporting bridge crew will surely be hoping to have a few more stories of their own, continuing their slow evolution from background players to actual characters – now we know that Lt Joann Owosekun (Oyin Oladejo) can hold her breath for 10 minutes, the sky’s the limit. It’ll be interesting to see what – if anything – is in store for Lt Keyla Detmer (Emily Coutts), Lt Gen Rhys (Patrick Kwok-Choon), Lt R.A. Bryce (Ronnie Rowe) and Lt Nilsson (Sara Mitich).

Third season newcomer Blu del Barrio also returns as Adira, human host of the Trill symbiont Tal, along with their boyfriend, Gray (Ian Alexander). Dr Culber’s efforts to give Gray – who can only be seen and heard by Adira – physical form will be a big part of the season, as Gray becomes more and more integrated with the crew. “For season 4 I’ve had a lot more hands-on involvement, like my suggestions for the future of Gray,” Alexander told Inverse. “They already have so much planned. Michelle [Paradise] and Alex [Kurtzman] already have this vision that I’ve very, very excited for everyone to be able to see.”

“Culber does make a promise in our season three finale to Gray that, ‘You will be truly seen,’” Paradise said on a Discovery panel at Outfest (via TrekMovie). “And we absolutely do pay that off in season four. That storyline and making sure we pay it off is hugely important.”

Anthony Rapp, who plays Stamets, added that Stamets, Culber, Adira and Gray will become a family in Star Trek: Discovery season 4: “Parenting – they’re not children but they are young people – the pressures of how to be available to be a mentor or guide or parent in the face of job responsibilities and sort of crises, that’s an interesting sort of sub-thread through the through the season… There’s more in the ways Paul and Hugh continue to evolve in their relationship. This is certainly explored also in this season.”

And there’ll be at least two familiar faces at Federation headquarters, where Oded Fehr (Admiral Charles Vance) and legendary movie director David Cronenberg (the mysterious Kovich) will be pulling some strings behind the scenes.

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Saru (Doug Jones) may have headed off to Kaminar but he still has a role to play in Star Trek: Discovery season 4. (Image credit: CBS All Access/Netflix)

Star Trek: Discovery season 4 plot: what can we expect to see?

Michelle Paradise is keeping her cards closer to her chest than The Next Generation crew at one of their regular poker games, though she did admit to TVInsider in January 2021 that the Discovery crew are hanging around in the 32nd century, rather than looking for a way back to their original pre-Kirk-and-Spock timeline. “I don’t expect that,” she said. “All of [the crew] knew going into that at the end of season 2 that this is a one-way trip. Now that they are here, we’re not looking to go back.”

What does that mean for plotlines? “I don’t want to speak specifically to themes, but we do have them!” she joked to “I think season 4 will absolutely continue the kinds of things we were doing in season three, in that we do have very strong themes that we’re exploring. Star Trek: The Original Series explored present-day things via sci-fi. And that’s what we did in season 3, and I think that’s just baked into what Star Trek does.

“Ultimately the thing that really resonates, I think, with people is, what are our characters experiencing? What are they going through? How are they connecting with one another? What are the challenges they’re facing and how do they overcome them individually and then as a family? All of that I think will continue.”

With the Emerald Chain out of the way, it looks like the threat in Star Trek: Discovery season 4 will be rather different this time out. The trailer reveals that the crew is dealing with a gravitational anomaly “five light years across”, rather than a specific human or alien foe – a force that, as Tilly explains, “could go anywhere, and we may not have any kind of warning at all”.

“We’re actually exploring – we’re diving deep into science – in the fourth season, in a kind of new and interesting way,” said Kurtzman in a panel hosted by Deadline (via TrekMovie). “There have been many kinds of villains over the course of Star Trek. What happens when the villain is not actually any kind of living, breathing entity, but something else? How do you solve that problem?”

Could we be looking at something technological Discovery season 2's hostile AI, Control? Or a lethal inorganic structure like the Crystalline Entity from Star Trek: The Next Generation? ScreenRant has suggested the rather plausible theory that the anomaly could be V’Ger, the rogue space probe from Star Trek: The Motion Picture. In the finale of that movie, V’Ger merged with USS Enterprise first officer Will Decker to attain a new level of consciousness – who knows what it might be capable of nearly a thousand years later...

We can expect Star Trek: Discovery season 4 to follow a similar structure to previous years, with each season based around a self-contained story arc, with just a few loose ends left untied.

“Discovery has that sort of serialized, season-long story baked into its DNA,” Paradise said in an interview with Inverse. “We also wanted to give the show a more episodic feel in season 3. We got to explore a story of the week or a villain of the week – it gives us time to explore some of our characters who we normally wouldn’t have time to explore. That was definitely a choice on our part and will continue on our show.”

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Michael Burnham (Sonequa Martin-Green) visits the Caves of Mak'ala on Trill. Expect more callbacks to earlier shows in Star Trek: Discovery season 4. (Image credit: CBS All Access/Netflix)

What questions does Star Trek: Discovery season 4 need to answer?

With the origins of the so-called ‘Burn’ revealed – who’d have guessed it was caused by a grieving kid with a symbiotic relationship to a planet made of dilithium? – and Osyraa and her Emerald Chain defeated, Star Trek: Discovery season 4 flies into uncharted waters.

Hopefully that means that Discovery and the crew can use the spore drive to truly explore the strange new worlds of the 32nd century – though, given this show’s love of callbacks to earlier series, it’s almost inevitable we’ll meet some familiar faces and species. (The presence in the trailer of a Federation official – possibly the president – who has a mix of human and Cardassian facial features suggests that those long-standing Deep Space Nine foes may be up for a comeback, this time in the Starfleet camp.)

Part of Starfleet's remit will be rebuilding a Federation that's a shadow of what it was 900 years earlier. The trailer suggests that many worlds will have to pull together to defeat a threat that affects Federation and non-Federation “equally” – as Burnham puts it, “We are not in this alone”. 

“The Federation is coming back together but it’s not fully back together,” Kurtzman told the aforementioned Deadline panel. “And so the continued mission of bringing other worlds in and meeting the criteria and standards of what it means to be a member of the Federation but also not to rob other cultures of their identity is something that we’ll explore.”

The biggest ongoing question Star Trek: Discovery season 4 needs to address is the nature of the ‘Sphere Data’, the ancient alien intelligence now integrated with Discovery’s databanks. Protecting it was the reason the ship made the one-way trip to the future in the first place, and it seems to be repaying the favor – first by helping the crew’s mental wellbeing, then by helping Tilly to forcibly eject the Emerald Chain from the ship. It’s a story that seems to be heading towards Short Trek episode ‘Calypso’, set in a distant future where Discovery is run by a sentient computer.

“‘Calypso’ is incredible,” Paradise told “And it is now a part of Trek canon, but specifically our show’s canon. It takes place many, many years beyond where our heroes are right now, and at some point, we will absolutely have to match up with that so that Discovery as a whole, including ‘Calypso’, all fits together as a piece.

“Certainly, bringing in that voice in episode four and having – we’ll call her Zora, she doesn't have a name at this point – but having her hide in the DOTs [helper robots on board Discovery] and be part of the story is the beginning of driving toward that. And eventually – who knows when? – we will absolutely have to make sure that we sync up with that.”

And then there’s the small matter of Stamets having issues with the way Burnham left his husband, Dr Culber, in a radiation-filled nebula in the season 3 finale. “I think that’s one they’ll get past in time,” Paradise said in TVLine.