The Doctor and the Kandyman knew each other, way back when they were both on Terra Alpha while she was a man who had an umbrella with a question mark-shaped handle. They have never seen each other since then, considering that the Kandyman was destroyed, at least until now.
"I knew I had to draw you out somehow, Doctor." the Kandyman said, the voice coming out of a mechanical voicebox inside of him, "That person there was bait, so that I could get you here."
"She had a name!" Jessica said before she had to be stopped from rushing the Kandyman by Khaldun.
"Really, Kandyman?" the Doctor replied, walking towards the Kandyman, "Because if I recall correctly, the last time we met each other, I ran you underground where you melted."
"This time, I have improved in terms of form. My speed and strength are far beyond what they were before."
"Cool. So, do you still have all that machinery underneath that shell?"
"Why do you ask?"
"Oh." The Doctor took out her sonic screwdriver and used it to dislodge the Kandyman's right arm. "No reason."
The Kandyman seemed unaffected by his arm falling off. "What did you just use?"
"Something to disassemble you enough to stop your takeover."
The Kandyman looked at the Doctor and smiled. "I have heard that this place's greatest religion states pride as a sin." He picked up his arm and put it to his shoulder, with said arm reattaching itself to his should through a series of extending caramel tendrils, to the group horror. "That is what will cause your doom, Doctor."
"So you heal yourself quickly now. How did you cover this poor woman in isomalt?"
"Because like you, I adapt. As an artificial intelligence, I can edit myself with ease, including producing the substance you describe. I will not be a victim of your trickery again."
"Doctor, what should we do?" Khaldun asked.
"The only thing we can do right now: Run!"
The trio ran out of the storage room and ended up at the refrigeration unit, and the Doctor got an idea. "I know how we can stop it!" she said, "Get all the soda you can and spill it on the floor!"
"The floor will be in a massive mess and it will get me fired!"
"It's either you get fired or the whole world gets covered in isomalt and dies! Now, soda!"
The trio got as much pop as they could while the Kandyman was getting out of the storage room. "Hey," the Doctor yelled, "you big stupid shambling pile of sugar!" The Kandyman started getting annoyed as the Doctor shook a bottle. "Have a drink!" She threw the bottle at the Kandyman, and the pressure from inside the bottle caused it to be a makeshift grenade, causing the bottle to explode and coat the Kandyman in soda. This caused him to start becoming solid and sticking to the floor. The Doctor looked at Khaldun and Jessica, barking "Shake those bottles and throw them! One isn't enough!" The others began shaking up the bottles and throwing them at the Kandyman, with each third of a litre adding more and more of a sticky coating until the Kandyman was completely stuck in place.
"Doctor!" the Kandyman said, uncharacteristically furiously from the voicebox, "I will have your head, and this world will be subject to my power!"
"You know what?" the Doctor said, taking out her sonic screwdriver again, "I doubt all of that." She used the screwdriver to short out the Kandyman's internal machinery, making sure he wouldn't bother the world again. She turned to Jessica and said "Sorry for the mess, Miss..."
"Burgess. Jessica Burgess."
"Ah. Got it. Although, as good as it was to stop him, I have a gut feeling that this isn't over."
"You froze that monster and shut it down. How the hell is this not over?"
"Because he's an artificial intelligence. As he said, he adapts. He could have made more of himself."
It was then that they heard sirens outside of the shop. Police sirens. The Doctor sighed. "Of course." She said, "This isn't the only place he put himself in this village. Are there other places here that sell confectionery?"
"Yeah. There are a few other corner shops in this town." Jessica replied.
"Good. Let's get to one of them."
"Not so fast." Jessica moved in front of the entrance.
"Move out of the way, Jessica. This isn't worth potentially letting the world get covered in isomalt."
"I'm not letting you go until you tell who, or what, you are."
"You want to know who I am?"
"Yes!"
"Well, Jessica, I'm the only one here who can stop this threat. I'll introduce myself better later, but for now, we need to get to one of those shops and stop another Kandyman from wreaking havoc, because I have a feeling that this Kandyman isn't the only one. Now, are you going to move out of the way and take us to that shop?"
Jessica nodded, and lead the Doctor and Khaldun to a corner shop nearby. It was completely caked in isomalt, surrounded by police. "What the hell happened here?" She asked.
"The Kandyman." the Doctor replied, "He did make more of himself."
"You know, Doctor," Khaldun said, "when you said that you were taking me into the future, I was not expecti-"
The Doctor elbowed Khaldun. "Khaldun!"
"I'm sorry. He's from the past?"
"Jessica, there's at least one more Kandyman out there trying to massacre everyone here. This isn't the time for questions anymore." The Doctor noticed something. "See the front of the building?" Jessica and Khaldun nodded. "Now, look to the left of that building." They all ended up noticing the trail going through the path on the side. "Jessica, where does that path lead to?"
"It leads to a street behind the shops and leads into the Sandhills. One of them has a big old hill in it."
"Black bench on the top?"
"Yeah, that's right."
This could mean only one thing for the Doctor. "That Kandyman's trying to get to the TARDIS. We need to stop it before it gets too late." The Doctor grabbed both Jessica and Khaldun by their arms. "Fasaeidan!" She ran, dragging the two hapless humans along with her, causing them to inadvertently run as well. They got to the Sandhills and began running up the hill, where the Doctor saw the Kandyman move up it. The Doctor managed to get to the Kandyman just as he was at the junction at the foot of the hill. "Stop right there!" she said, with both Jessica and Khaldun behind her.
The Kandyman turned around, looking like he was covered in diamond-shaped gummies. "Ah, Doctor." he said, "You didn't think that it would be that easy for you this time?"
The Doctor took out her sonic screwdriver again. "Actually, it is." She used the screwdriver, hoping to short-circuit this Kandyman as well, only for nothing to happen. "How did you-"
"Become unaffected by your little trinket? I had sensed that one of my copies was destroyed, so while I was making my mark inside of the store you just ran past, I learned what your "screwdriver" does, and adapted my shell to make it immune to it."
"That's what that texture is for, isn't it? Because the sonic screwdriver works by using soundwaves, it cannot penetrate through soundproof surfaces."
"Now, if you try to fight me, I will cover you and your acquaintances in isomalt, yet if you let me into your little spaceship, you will be sorted once this planet becomes subject to my fellow workmen in the Happiness Patrol."
"Like hell am I going to let you into my TARDIS! As long as I'm still standing, no planet shall be under your caramel thumb. If that means that I die because of this, so be it."
The Kandyman opened his mouth, showing a tube ready to spew isomalt at the crew. "Goodbye, Doctor."
It was then that Jessica found a pebble on the ground and threw it at the tube, where it jammed itself inside.
"What is this?" the Kandyman said through his voicebox.
"Can't shoot us if the tube's blocked." Jessica replied, "That substance you use will build up inside as a result."
"...leading him to explode!" the Doctor proclaimed, "Jessica, you're a genius!"
As the isomalt built up inside of the machine, it started to leak or of certain parts of him. "This isn't over!" He yelled just before he exploded into a scattered bunch of confectionery and isomalt, which ended up crystallising. The trio looked at the man on the black bench.
"You saw nothing." the Doctor said, "Understood?" The man nodded and walked up the hill. "If he managed to make another one of himself, then there must be somewhere where he's able to create clones. There needs to be somewhere where something of that calibre could rest. Let's search around the surrounding villages. Maybe then, we could fine its main sour-"
It was then that the trio heard a yell at the top of the hill and ran to it. The man that was on the bench was staring off in the distance in shock. The trio looked at where he was looking: the Penshaw Monument, one of the biggest attractions in the whole of Sunderland, covered in isomalt, turning it into a vibrant shade of blue rather than its usual black brickwork.
"Well," the Doctor said, "we found where the Kandyman rested himself."