"Death is an increasing problem," Rafando explained as he and Arthur walked around the lake. "With over a billion intelligent species active in this galaxy alone, it is an ever-greater challenge to know how to kill all of them. On this planet, we are proud to serve as executioners to every living thing. The destruction of a Time Lord, however, is a particular honour."
"I can see that," Arthur remarked, recalling how he was summoned by a woman in black cloak after he had dinner with Nardole, asking for his role as an executioner. Nardole had warned him that he will meet his and the Doctor's younger versions before he goes with the woman, telling him nothing but to trust his instinct.
"This technology is precisely calibrated. As you can see, it will stop both hearts, all three brain stems, and deliver a cellular shock wave that will permanently disable regenerative ability."
"I understand."
"Now. Following termination, the body will be placed in a Quantum Fold chamber, under constant guard for no less than a thousand years. In case of, shall we say, relapses. Life can be a cunning enemy. An additional stipulation of the Fatality Index is that the sentence must be carried out by another Time Lord."
Arthur frowned. "Why did you have to summon me to be the executioner, not the Doctor? He's also a Time Lord."
"We believe that the Doctor—your father—isn't the right person to do so. We know that he had…history regarding the prisoner."
"But I had history with her as well."
"But not enough to be attached," Rafando denoted. So in summary: they summoned him to kill Missy because he had no personal grudge against her and was willing to do so without any hesitation. At least, when he's ignorant about what her past self had done to him in his distant future.
Maybe Arthur didn't know what Missy/Master would do to him. But he knew how cruel this person was to his father, Clara, and Claudia. How many lives Missy/Master dragged down for an old problem with the Doctor. That too should be included in the 'personal grudge' index.
"That's not a wise choice," someone said, making Arthur and Rafando turn their heads towards the Doctor who was standing not far away. His blue eyes continued to glare at Rafando as he walked towards him. "Seriously. Choosing Sunny as the executioner? You and your community have lost your minds."
"Your son is a wise choice, Doctor," Rafando defended in a firm tone, as if exasperated that the worst-case scenario was happening. "We know your history with the prisoner."
"Then you should know what happened with Sunny in his hands."
"That's still too far away."
"Not for me," the Doctor scoffed. "For me, that event happened in the past. A mistake that I regret to this day. I'm not willing to let Sunny become a murderer."
Rafando sighed softly, giving his colleagues the 'I tried' face. "In that case, I'll leave the executioner duties in the hands of another Time Lord, the Doctor. Are there any protests?" Everyone was silent. "Then, take out the prisoner."
A door behind the Doctor opens, and Missy steps through. "Oh! Doctor! Arthur! I didn't expect you two. Thought you'd retired and be," she waves her hands off despite the chains around them. "You know. Family dinner on Darillium, that's the word among the Daleks. What happened?"
The Doctor looks down, holding his son's arm while Arthur rubbing his nose, recalling the conversation his parents had in Darillium. He knows that isn't the last time he will see his mother, but for his father, it is.
Missy quickly realises their expression. "Oh, I see. My condolences."
"I don't need it," Arthur simply responded, letting Missy walk towards the dais. The Doctor walks to the side by the lake, looking at him without any emotion on his face.
"The prisoner will kneel," Rafando ordered and two guards move to take Missy's arms.
"Right," Missy remarked as she stepped onto the dais and kneeling. "Thank you."
A cube rises from the lake. Arthur quickly realises it as the Vault. He had a guess who the person inside the Vault might be (judging by how firm the Doctor was regarding him entering itjudging by how firm the Doctor was regarding him entering it), but now he had his confirmation.
"The Quantum Fold chamber is prepared," Rafando announced.
"Great," Missy commented.
"The sentence will be carried out. Executioner?"
The Doctor moves to face Missy, and puts his hand on a long lever.
"Please, I'll do anything. Just let me live," she pleaded.
"After everything you had done to me? To my companions? To my family?" The Doctor demanded, eyes glaring at his former best friend. His mind pictured the lives of the thousands who died at her hands, the torture she inflicted on his comrades for pleasure, the suffering she inflicted on his new family after the Time War…
Arthur looked at the scene in front of him with mixed feelings. Was he happy that this villain in front of him was going to die? To be honest...yes, he was happy. But as much as he wanted justice to finally be served properly, seeing his father about to sentence someone to death... Arthur felt sick.
Right when he turns around, he sees a cowled figure is approaching. "Doctor?" he called, gesturing to the mysterious figure.
"Have you requested a priest?" Rafando asked.
"Well, I haven't," Missy quipped.
The figure gestures to both of them to approach. "Apparently, we have," the Doctor realised.
"I shall seek consultation," Rafando affirmed as he used his wrist computer. Missy sighs and sits back on her heels. "There are 412 precedents in the Fatality Index. Divine intervention, therefore, is permitted for a maximum of 5 minutes."
"Can't you make it longer?" Arthur wondered, which he simply gave him a stern look. "Right."
"The executioner and his acquaintance may now discuss his immortal soul and any peril thereunto."
The Doctor steps out of the dais, gently holding Arthur's hand as they both walk over to the cowled figure.
"Greetings, sinners. Only in darkness are we revealed," the figure said, reading a book.
"We never sent you," Arthur recalled, but tilted his head at those words. Why does that sound familiar? "Who are you?"
"Goodness is not goodness that seeks advantage. Good is good in the final hour, in the deepest pit without hope, without witness, without reward. Virtue is only virtue in extremis. This is what he believes, and this is what he taught to our son. And this is also the reason above all, I love him. My husband. My madman in a box. My Doctor." The figure pulls back the cowl to reveal himself as Nardole. "Your missus wouldn't approve."
"How the hell did you get here?" The Doctor demanded.
"Followed you from Darillium, on the explicit orders of the mother of your son, River Song. Warning, I have full permission to kick your arse and reprimand your son," Nardole pointed out. "I also need to pick up your future son in the Library."
Arthur looks behind Nardole to find another mysterious figure leaning on a rock. The man wears a simple green hoodie and he waves his hand at him with a small smirk. "I don't know if I can make the right choice, Nardole," he confessed. "After all Missy/Master had done…it sounds selfish for me to save her."
"Your mother used to tell me that you are the most selfless person she ever knew, and she is always proud of that. Trust yourself. Because remember, sinners, in darkness, we are revealed."
"I regret, gentlemen, this consultation is over," Rafando reminded them.
"I regret it, too," Missy added.
"The sentence must now be carried out."
"Well, take a few more minutes if you like. Knock yourself out. Actually do. Do that. Knock yourself right out."
The Doctor returns to the dais and Nardole pulls down his cowl. Arthur simply watches the scene in silence.
"I'll be good, I promise. I'll turn, I'll turn good. Please. Teach me, teach me how to be good," she begged, close to tears. The sight left Arthur unsure what to do.
"Without hope. Without witness. Without reward," the Doctor recited. He remembers saying what Nardole said earlier to Arthur when he was born, and River once commented that they were too hard to understand for a newborn.
"I am your friend."
"Makes no difference."
"I know it doesn't. I know I'm going to die for all the crime I committed. I have to say it, the truth. Without hope. Without witness. Without reward. I am your friend."
The Doctor looked at his son once more. His brown eyes looked back with approval, trusting that whatever action he would take, he would help her. Without any hesitation, he pulls the lever. Energy surges from the four columns into Missy's body and she collapses in a small cloud of smoke. The Doctor turns away. "On my oath as a Time Lord of the Prydonian Chapter, I will guard this body for a thousand years," he vowed.
The two guards step forward to remove Missy's body. The woman moves around. "Oi! Get off. Get off! I've just been executed. Show a little respect," she huffed.
"She's…she's alive," Rafando realised.
"I was just a bit sleepy, all right? Let's not split hairs. Shut up. Thanks for that," she commented, looking at Arthur before looking at the Doctor. "Night-night."
"Of course she's not dead. She's a friend of mine," the Doctor denoted as Missy fell asleep. "Sunny has fiddled with your wiring a little bit."
"You swore an oath," Rafando reminded him.
"To look after her body for a thousand years," Arthur elaborated. "Nobody mentioned the dead body."
"You both cannot do this. You will not leave this planet alive."
"Do me a favour. The Fatality Index. Look up the Doctor," the Doctor suggested.
"You have an entry, just like any other sentient being. Even your son has one."
"Look Under Cause Of Death," Arthur added with a smirk, tilting his head at Nardole so he can get closer.
Rafando works his wrist computer. It ticks rapidly as it runs through all matching entries. "Your father does seem to have a…an impressive record of fatalities credited to him." The ticking keeps going, and speeds up. "A truly remarkable record."
"That's your cue to run," the brunette man told the others, to which they complied.
"Where are you going? He's unarmed!" Rafando yelled, glancing at both of them. "You are unarmed? Both of you?"
"Always," the Doctor answered.
The wrist computer still hasn't stopped scrolling through. "You stand alone?"
"Sometimes."
"You're the one who should be afraid."
"Never," Arthur disagreed, giving him a dare look.
"Have a nice day, then," Rafando said with a nervous smile before running away in fear.
Arthur snorts at the way those people run. "Come on, Nardole," he told Nardole. "We need to get Missy to the Vault and find the safe location."
"Any idea?" the Doctor inquired as he helped Nardole to carry Missy.
"I know a place."