Warning: Spoilers ahead for Doctor Who season 15, episode 7, "Wish World."Sienna-Robyn Mavanga-Phipps' Captain Poppy has had a shock return to Carole Ann Ford's comeback as Susan. Famous for her time as Doctor Who's first companion, Susan traveled with William Hartnell's First Doctor from 1963 to 1964, racking up an impressive total of over 50 appearances during that time. Her return in "The Interstellar Song Contest" promises to tie up important loose ends and address some unanswered questions.

Although Poppy's debut was only in 2024's "Space Babies," Susan hasn't appeared since Doctor Who season 15 cast reinforces showrunner Russell T. Davies' recent proclivity for delving very deep into the show's vast lore. Part of what makes Susan so interesting is the fact that she is the Doctor's biological grandchild, providing a rare glimpse into the genetic family tree of Doctor Who's main character. The identity of Susan's parents remains a mystery, but Doctor Who could be ready to change all that with the return of Poppy.

Doctor Who Season 14 Cast Doubt Over Susan's Mother

Fifteen discusses the children he is yet to have a couple of times during Gatwa's first run

The Doctor has only ever had one onscreen "daughter." In Doctor Who season 4, episode 6, "The Doctor's Daughter," Georgia Tennant played a rearranged clone of David Tennant's Tenth Doctor called Jenny. However, the show hasn't referenced her since, despite the twist that she actually survived the end of the episode. While it's possible that Jenny is Susan's birth mother, I think it's unlikely. While Ten had already alluded to the fact he was once a father during Tennant's first season, Ncuti Gatwa's Fifteenth Doctor made things far less clear and more timey-wimey in season 14.

In "The Devil's Chord," Fifteen even mentions Susan by name while explaining to Ruby Sunday (Millie Gibson) how complicated his timeline can become.

Basically, the Fifteenth Doctor suggested on more than one occasion during Ncuti Gatwa's inaugural run that although Susan is indeed his granddaughter, he has yet to father any children himself. So, in a twist that only a show like Doctor Who can pull off, the Doctor has met and bonded with his grandchild before even producing offspring. He says as much in both "The Devil's Chord" and "The Legend of Ruby Sunday." In "The Devil's Chord," Fifteen even mentions Susan by name while explaining to Ruby Sunday (Millie Gibson) how complicated his timeline can become.

With Doctor Who season 15 now paying off other season 14 moments that seemed innocuous at the time, I think it's likely that the Doctor's mentions of at least one of Susan's parents are about to become far more important. The matter of the Doctor's children has been lightly addressed during the show's storied history, but the references to both them and Susan have ramped up significantly in the last two seasons, and it's becoming impossible to ignore.

The Doctor Says Poppy Is "Real" At The End Of "Wish World"

Poppy could genuinely be the Doctor's daughter

Doctor Who season 15, episode 7, "Wish World," shows the Earth in a state of fantastical rearrangement. The planet's retrofuturistic aesthetic isn't the only change, as the memories of everyone on the human homeworld have been altered to align with an idealistic narrative being put into place by the returning Conrad Clark (Jonah Hauer-King) and the youngest member of Doctor Who's Pantheon to date. One of the most notable changes is that Fifteen and Belinda Chandra (Varada Sethu) are married, and Poppy is their daughter.

The Doctor and Sethu's character go by John Smith and Belinda Smith respectively during their entranced states in "Wish World."

Because so much of Conrad's version of the Earth has been altered, the implication is that Poppy's presence as the Smiths' daughter is just an extension of the spell being cast over them by the God of Wishes. However, when the Rani (Archie Panjabi) cuts the Doctor loose from the Bone Palace, his confused memories start to resurface. During the fall, Fifteen starts to more accurately who he is, saying that Poppy is "real," which suggests she actually is his daughter rather than just a deception. After all, Poppy did call him "Daddy" when they met in "Space Babies."

If the Doctor is claiming that Poppy is his biological offspring, she could eventually grow into the offscreen mother of Susan.

If the Doctor is claiming that Poppy is his biological offspring, she could eventually grow into the offscreen mother of Susan. While this would be a pretty exciting reveal, it would still omit the identity of both Susan's father and Poppy's mother. That being said, there is no telling just how long the Doctor and Belinda have been under the influence of the Rani's master plan, and unsure of who they really are. Therefore, it's possible that Belinda is just as much Poppy's mother as the Doctor is Poppy's father.

Poppy's Return After "Space Babies" Feels Too Significant To Ignore

The Doctor's reunion with Poppy is too conveniently timed

The ending of Space Babies didn't seem to have any larger significance at the time beyond the episode drawing to a close. Everything seemed to conclude neatly, and I never expected to see any of the story's titular infants ever again. So, when Poppy recently came back for a brief cameo in "The Story and the Engine," I figured something big was going on. Now that she has had a more substantial comeback in "Wish World," I'm convinced that Poppy's presence is far more than just a fun little nod to "Space Babies."

While Susan's comeback would obviously be a landmark moment for the show at any point, it would be a strange move for Davies to bring back a seemingly minor character like Poppy at the same time without reason.

Susan's return has also been timed far too conveniently for it to be a coincidence. I'm sure Carole Ann Ford's Doctor Who comeback is connected to Poppy, and the ongoing and resurfaced mystery of Susan's lineage seems like the perfect vehicle to bring the two characters together for a big reveal. While Susan's comeback would obviously be a landmark moment for the show at any point, it would be a strange move for Davies to bring back a seemingly minor character like Poppy at the same time without reason. Poppy's return would just be overshadowed.

Of course, there is the worrying fact that Davies has already bailed on the chance of a satisfying origin story in Doctor Who season 14. Ruby's mother was teased to be a special and/or powerful being throughout Millie Gibson's time as a main cast member, but Davies opted to make her mother a regular human who just wasn't ready to be a parent. I'm holding out hope that there is more to Ruby's storyline, but there may not be anything left to reveal. So, I'm concerned Doctor Who season 15 will end similarly for the Poppy/Susan twist.