Warning: spoilers ahead for Doctor Who season 15, episode 1.

Ncuti Gatwa's Fifteenth Doctor is something of a social butterfly, as Doctor Who announced Varada Sethu as Gibson's replacement.

Sticking with present-day England as his primary scouting pool for potential TARDIS talent, the Doctor finds Sethu's Belinda Chandra unwillingly embroiled in an intergalactic war started by Alan. The Doctor rescues Belinda, naturally, and she becomes his new partner by default after returning to her native time period proves a temporal impossibility. This cements Belinda as the next Doctor Who companion following Ruby Sunday's departure, but season 15's premiere confirms Fifteen actually had two other companions between Ruby and Belinda.

The Fifteenth Doctor's FOUR Companions In Doctor Who Explained

Fifteen Has A Companion For Every Season

After being unceremoniously ditched by Ruby Sunday, the Fifteenth Doctor's next companion, as shown in the 2024 Christmas special, "Joy to the World," was Anita, played by Steph de Whalley. Despite Nicola Coughlan's Joy being the more prominent character, she shared minimal interactions with the Doctor. By contrast, the Doctor and Anita enjoyed an entire year together at the Sandringham Hotel, during which the Time Lord spoke at length about his feelings and adventures.

They may not have traveled far, but the Fifteenth Doctor and Anita developed a strong emotional connection, making her just as important as official companions like Martha Jones or Dan Lewis - arguably, more so. A tender parting scene confirmed how deeply the Doctor's friendship with Anita ran, even if most of that bonding took place offscreen.

After abandoning Anita, the Doctor then found himself trapped on Missbelindachandra for six months after his TARDIS got confiscated by evil robots. It was here that he sparked up a partnership with Evelyn Miller's Sasha 55. While Sasha only appears briefly in Doctor Who season 15's "The Robot Revolution," the episode reveals that she helped the Doctor from the first moment he arrived, meaning the pair likely spent every day of the six-month time jump in each other's company.

That alone is enough for Sasha 55 to be allowed entry into the Doctor Who companion club, but she also mentions taking to the stars once Missbelindachandra's robotic overlords are thwarted. This line strongly implies that Gatwa's Doctor has already made up his mind to take Sasha as a permanent companion once his TARDIS is returned, and the two friends have even discussed their future traveling through time and space.

The Doctor's Adventures With Anita & Sasha 55 Were Bigger Than We Saw

It's Time For Big Finish To Step Up

Anita and Sasha 55 may be minor characters within the grand scheme of Doctor Who, but both are far less minor in the wider tapestry of the Doctor's life. The Doctor was stuck letting time naturally at the Sandringham Hotel for a year, and "Joy to the World" showed him doing routine maintenance to pay the rent. But as Doctor Who has so frequently proved over the years, Earth is only ever a Dalek fart away from danger. It seems very likely that the Doctor would have found a mystery he couldn't resist solving while at the Sandringham, and Anita would have been the companion helping him to solve it.

It's a massive story that Doctor Who season 15 glosses over.

Likewise, the Doctor's six months with Sasha involved plotting the downfall of a tyrannical cyber regime, with the Time Lord evidently becoming the rebellion's leader and chief planner. Doctor Who might not show it, but the Doctor assuming control over a planet's freedom fighters represents a much larger, untold story hidden beneath the surface of season 15. The Doctor has developed relationships with other member of the alliance like Manny, and almost certainly made tough calls that endangered lives, all with Sasha 55 at his side. It's a massive story that Doctor Who season 15 glosses over.

Plenty of one-off Doctor Who characters have returned in audio adventures, from Jenny to Jago & Litefoot.

The beauty of Doctor Who, of course, is that another channel of the franchise can explore these narratives. The Big Finish audio adventures could pick up Fifteen and Anita's story, chronicling their escapades solving crimes around 2024 London, Sherlock and Watson-style. After "The Robot Revolution," Big Finish can now also examine the Doctor and Sasha's efforts to overthrow Al on Missbelindachandra. It would be especially fascinating to see whether such an environment, combined with the isolation of not having a TARDIS, brought a small part of the War Doctor back to the fore.

The Fifteenth Doctor's Revolving Door Of Companions Says A Lot About Gatwa's Incarnation

The Doctor Should Be Concerned About His Ever-Changing Companions

The fact that Ncuti Gatwa's Fifteenth Doctor has already burned through three companions says a lot about his incarnation - some of it good, some of it less so.

Starting with the positives, it could be argued that Fifteen has learned the value of moving on. Regenerations gone by would occasionally swear off companions after experiencing particularly painful losses, and Fifteen did something similar after Ruby Sunday's exit. Since then, however, Gatwa's incarnation has swept from Anita to Sasha 55 to Belinda Chandra without hesitation. Sasha's disintegrated remains have barely hit the ground before Fifteen starts mentally picking out Belinda's bedroom in the TARDIS.

Perhaps the Doctor's newfound ability to move on from departed companions requires him to think of future companions as transient, temporary engers.

Fifteen has possibly also ed that a Time Lord traveling alone is a dangerous thing. From Ten's Time Lord Victorious era to Twelve's post-Clara malaise, it is very clear by now that the Doctor always needs a person to ground him. The current Doctor's ability to find new companions wherever he goes is one way of ensuring he never makes that mistake, so he takes a minute to quietly shed a tear for them, then gets on with the job.

On the other hand, the Doctor losing three companions in quick succession is a lot like trashing three cars in quick succession - at some point, it might be worth looking at the driver. Even if one accepts that Ruby Sunday's choice to leave was no reflection on the Doctor himself, his record since is still patchy. Anita didn't even receive a TARDIS invitation, despite clearly wanting one. Sasha 55 died six months after becoming the Doctor's new best friend and was rapidly replaced. Belinda complains about having her DNA tested without consent only moments after stepping aboard.

Perhaps the Doctor's newfound ability to move on from departed companions requires him to think of future companions as transient, temporary engers. In previous Doctor Who eras, the Doctor dared to dream that he could travel with Rose Tyler, or Amy Pond, or Donna Noble, or Clara Oswald until their mortal lives ended, and found himself disappointed each time. To protect his own hearts, Gatwa's Fifteenth Doctor may have started accepting that any new companion he lets into his life will be leaving, alive or dead, belong long.