Next Time: The Girl Who Died

But how would that music have been created in the first place? First, let’s catch up on where we ended with last week’s episode, “Under the Lake”: Clara was trapped underwater in the mining base known as “The Drum” with Cass and her sign-language interpreter Lunn, while the Doctor traveled back in time with Bennett and O’Donnell to uncover the mystery of the odd alien spaceship and the markings it contains. But Clara doesn’t want to face death again and even tells him that he owes her, he’s made himself essential to her, and “If you love me in any way you’ll come back”. Oh, and there is an enormous wrapped corpse in the middle of the ship. The Doctor demands to know how he’s turning people into ghosts and for what goal, but Prentis has no idea what he’s talking about. He, Bennett, and O’Donnell have already met the Mole, a sniveling Tivolian named Prentiss who’s come to bury his former enslaver, the Fisher King. “You’ll have to watch and see”. In the words of the Doctor, “Google it”. The Doctor has lived long enough to know better.

The Fisher King also taunts the Doctor about how he “slavishly” protects time and would rather die than change a word of the future. After upsetting Clara by announcing that this means he must die, he asks to speak to her alone.

Simon Ridgway/BBC Worldwide Paul Kaye as Prentis and Peter Capaldi as the Doctor.

Back on the ship, Clara sees O’Donnell’s ghost, who takes her phone.

“Doctor Who” fans know Jenna Coleman is leaving the series, meaning the end of Clara Oswald’s adventures with the Doctor (Peter Capaldi).

Bennett hears her screams and runs after her, the Doctor in pursuit. He’ll break the rules if he has to.

The Doctor decides to go back to the base, and not die, because no one will stop him-except the TARDIS that will not let him leave his time stream, and instead sends him back 30 minutes. The Doctor reluctantly admits that Bennett is right.

As the Doctor points out, Tivolians and the Fisher King are really two sides of the same coin. Hiding in the shadows, the Fisher King’s character design initially seems mysterious and creepy but it gets less impressive the more we see of it when it becomes obvious it’s a guy knocking about in a suit. Turns out he’s an undertaker, carrying the coffin of a creature called the Fisher King that invaded his planet. And by the episode’s end, the Doctor hasn’t done anything to prove him wrong about that. He uses the power cell from the ship to detonate the base’s dam to kill the Fisher King and the TARDIS starts up its emergency protocol with Bennett inside.

Nothing else matters as much as Clara’s life in the Doctor’s mind and that’s the best reason to kill her off.

Simon Ridgway/BBC Worldwide Bennett confronts the Doctor about the loss of O’Donnell. While the major theme in Season 8 was whether or not the Doctor is a good man, Season 9 finds the Time Lord obsessed with making sure Clara is safe, regardless of the consequences. Lunn is willing (though not thrilled), but Cass protests. Just the kick the Doctor needed to solve the riddle of this episode.

Both the Doctor and Clara got lectured for their cold-bloodedness. Of course, there’s always a much worse possibility. In a way, the role of the companion is always a tragic one.