Space, Year 1998: 

The Doctor was with Daniella in the library. Each one had a pile of books to read. Daniella already read all of her diaries but she found nothing useful.

"Doctor, can you explain why it is a paradox?" She was curious.

"Why are you asking now?" He asked her.

"I'm reading something about a semi-paradoxal event and it's similar to ours." She replied.

"As your book supposedly explains, a semi-paradox is when a person from the future or past meets a blood related person or itself from another time." He was struggling to find the easiest words to explain, "Basically, some weird things are going to happen around them without even creating a real paradox." He paused and then continued, "We met him in 1998, year of disaster movies like Titanic, Armageddon, Godzilla. Biggest pop culture event happened this year, Who wants to be a Millionaire, Charmed, The 70's show, the end of Doctor Quinn. Also big political events, this year shaped the future. This year has something special. It has a message and an importance for Earth. It's not a coincidence we met him in 1998. His meeting is important and clues about who he is and why he is here are given by everything that happened in 1998." The Doctor wasn't even breathless after his speech.

"I see. Complicated." She continued reading her book and then she said "Do you like Mac? You know he has feelings for us."

"I know. I'm an old man, not in the mood of falling in love."

"What if something happens between you? Will you reject him?"

"No. I like him a lot. Every person who loved me suffered. They all sacrificed their lives for me. Some died, went missing." He stopped," Love is not for me anymore. With Mac it could be different. We are both aliens, our feelings work differently from humans." The Doctor sometimes could be very open about his feelings.

"You are not opened but not closed. I understand you don't want to hurt him. You are being a protector."

"And you? He loves you too." The Doctor asked.

"Love is not for me. I've never loved someone." She replied.

"We don't choose loving. It chooses us at the right time. Like choosing the best compagnons at the right time."

"It's flattering but I did choose you. I decided to follow a stranger through time and space."

"You decided because you wanted to study me."

"And you didn't let me do it properly." Since their encounter the Doctor gave just small information about himself just to not let Daniella finish her work. He was afraid she would leave. "I like being with you. It will last forever."

"Not forever no." The Doctor whispered.

Meanwhile, Mac was coming with his plan to discover more information about the man. He has one thing in mind: seduction.

“Are you awake?” Mac asked the man.

“Yes. I had a nightmare."

“Tell me about it.” Mac said curiously.

“It's dark. I saw corpses. One in particular was coming back often; the dead body of a woman. They were all saying: it’s your fault you killed us.

“Sad story.” Mac told him. He wasn't moved by his story.

“I can’t get these images from my mind. I’m feeling guilty for something I know nothing about." Those images were killing him slowly.

Mac saw his weakness and he knew what he needed to do.

“I can make you forget about it. Let me just..” Mac changed his face to the one of a woman. His body was skinnier. His blonde hair grew longer. Mac looked like Lady Godiva, naked with only hair to hide his body.

“Do you like what you see? You like seeing me naked?" Mac got closer to him and tried to kiss him but the man pushed him with disgust. “You prefer men maybe.” He changed back to his past form but still naked. “ Better?”

“ Are you sick? Why are you doing this? I don’t want to have sex with you. Leave me alone, pervert.” The disgust of the situation could be read on the man's face.

“I’m sorry I didn’t mean to offend you. I just wanted to know more about you. About who you desire and are." Mac got closer and touched the man. His appearance changed again. He looked at the mirror and saw the face of the man. He took the appearance of the amnesic man. “What you desire the most is yourself." He had no words left. "I'm sorry. I understand now. You don't seem like a threat."

"I'm not one. I'm as lost as y'all."

"Accept my apologies. I tried to use my abilities to see if you were hiding something but it seems not." Mac was lying. His goal was to get the trust of the man to know even more than he could have by having a one night stand.

"I forgive you. I understand your actions. I'm a stranger with no memories. How could you trust me?" He sighted, "You seemed worried earlier. Did you discover something about me?"

"You are one hundred percent human. It's a good thing." Mac was lying again. "Do you know which city it was in your nightmare?"

The man was trying to remember the small background details he could have seen. "I think it was London."

"Let me check something in the library." Mac left to see the Doctor.

"Doctor, we are in great danger. He had a nightmare with a post-apocalyptic London. He named the planets of the three deadliest beings of the galaxy. He desires himself. Who, apart from you, desires himself?" Mac was panicked. He understood the threat the man could be, especially for the man he loved.

"I know. The semi-paradox tried to warn us. I think I know who he is." The Doctor said.

"Who?" Daniella asked.

"We need to find one of my old friends. He can help us find something."

"What?" Daniella was not hoping to have an answer but she had one.

"The RETGAIN. A powerful pill that can help him have his memory back. Only chance but risky."

"Would he accept to take this pill if it's risky?" Mac asked.

"Don't know. If he says no it means he remembers everything. Only someone with real amnesia will be capable of risking its life."

"So where are we going?" Daniella was happy to travel somewhere else, she was tired of wandering in space.

"London, 2004." The Doctor said.

London, Year 2004:

The team arrived in a dark, smelly underground. It seemed like an abandoned underground passage. It was a wetland in those tunnels. Every move or noise could be heard even from 1000 kilometers from where the person was.

“Be quiet.” The Doctor said, “If he hears us, it will spoil the surprise.”

After a long walk, they arrived in an abandoned underground platform. It was converted into an office. A man with a long blue coat was standing working on a computer. He didn’t even turn his back when he started talking to his visitors.

“Hi Doctor. It has been a while.” The man said.

“Jack. Always so..” The Doctor got interrupted by Jack.

“Handsome.” He turned to see the Doctor’s face. “Oh, you are old. At least, you still have a nice bottom.” Jack Harkness got closer to the Doctor and his compagnons. He looked at Daniella. “Hello. Captain Jack Harkness.”

“Hi. Daniella. This is Mac and there is a man whose name is unknown.” She said without flirting with Jack.

“Why is she not flirting?” Jack asked the Doctor. “Since when do you have compagnons who do not like me?”

“I like you. Very sexy. I could be whoever you want in case you want to, you know what.” Mac winked at Jack.

“Stop it you two. We are not on Tinder.” The Doctor hated when Jack was flirty with everyone he was meeting. “We have an issue and need your help, Captain.”

“I suppose it is about this man.” He looked at the amnesic man. “Or is it about another blonde girl?”

“Who?” Daniella asked the Doctor.

“A girl not as pretty as you.” Jack replied and winked at Daniella.

“There is a time and place.” The Doctor said. He was already tired of Jack. “Now, tell me. Do you have the RETGAIN?” Jack was suddenly being serious.

“It’s been a while since I have had it. You want to use it on him. With all my respect, Doctor, it’s risky. It could kill him.”

“I’m ready to do whatever it takes to get my memory back.” The amnesic man said.

“Well..” Jack gasped, “ 10 years from now, UNIT and Torchwood worked together to develop a little pill capable of helping regain memory. It’s basically the contrary of the RETCON which can whip out parts of the memory. UNIT was being too ambitious and some rival companies learned about our breakthrough. Torchwood decided to hide far away from her so that no one uses it with bad intentions.”

“No, you gave it to them. You went to their secret base. How?”

“Doctor, I’m immortal. I can do whatever I want.” He stopped for a bit, “The Sontarans are the best to protect it. One of the most powerful armies. They know the danger, they won’t give it to anyone. No need to worry.” Jack was feeling the Doctor was worried. “Doctor. You have trusted me multiple times.”

“Let’s get our little pill back. Mac, you stay here with him. I go with Daniella and Jack to the Sontarans.”

“Alright. Do you have something to pass the time? Games? Toys?”

“I have toys but not the one to play with him.” He winked “Just with me.”

“Is he always like that Doctor?” Daniella asked, “Too much dick centric.”

“He is being soft. He is the worst.” The Doctor remembered all of the dirtiest jokes from Jack.

Daniella, Jack and the Doctor said goodbye to their two friends and went on board of the TARDIS for another trip.