There are ten tall figures waiting for her at the entrance in what she assumes as their fortress. The ten figures have pale white skin and white hair with bright blue eyes. She also notes their armor and weapons made of ice. The ten white walkers simply watch her in silence as she walks towards them. Upon closer inspection, the white walkers look like the Sidhe in her old world.
One white walker steps forward and gestures for her to follow him.
Harriet allows the white walker to lead the way as they enter the fortress. She is soon followed by the rest of the white walkers. The walls on either side of her are made of ice with some strange runic etchings covering it. Harriet might need to study them to better understand the runes. If only the Night King let her. She might have to inquire about them soon.
She continues to walk through the icy hallways for two minutes until they finally reach a cavernous room, where she immediately sees the Night King sitting on a throne. She also notes that there are more of the white walkers gathered around here.
"Greetings, Night King," She says in the Old Tongue, her voice echoing around the cavernous hall.
"Greetings Lady Potter. What is your intent for coming here?" The Night King asks coldly.
Straight to the point, she thinks in amusement.
"I have come to your domain to make a deal with you," She replies just as cool.
"What kind of deal?" The being asks almost curiously.
"I intend to make a magical community out of the Wildlings Beyond the Wall. All I ask is that you stop harvesting the dead bodies for your army. I also don't want you and yours to harm anyone in my future community," She tells him.
There is a brief pause while the Night King contemplates her request.
"And in exchange for what?" The Night King inquires.
"Anything you want," comes Harriet's nonchalant reply.
There's another pause while the being regards her thoughtfully.
"I can sense great power in you. What are you?" The Night King suddenly asks.
"I've been given many titles and names. But most know me as the Mistress of Death," is Harriet's honest reply.
"Yes, I can sense Death surrounding you," the Night King nods his head. "As for what I want, I have decided something after seeing your power for myself."
The Night King stares at her for a moment before resuming, "Here is my proposition. Will you do me the honor of becoming my wife and bearing my children? And in exchange, we will no longer add your future people to my army and we will not harm them so long as you uphold the end of the deal."
Harriet suddenly realizes that Night King was far too ambitious. He must have sensed her immense power and that's why he proposes to take her as his wife and bears him his children. The Night King wants her for himself.
Well, she doesn't have a problem with his proposal. It's been a while since she has taken a husband, and her children and her descendants were all dead many, many years ago. Perhaps marrying the Night King isn't such a terrible idea. He already has a standing army just waiting to be deployed. If war breaks out or the south intends to invade the far north, then she'll just ask her future husband to send his undead army down south while the magical community remains uninvolved with the war.
She also doesn't care about moral dilemmas and striking a deal with a powerful Necromancer. She has lived for thousands of years and she no longer has any care about what is right and wrong so long as she gets her main objective. This is not her first time working or even marrying a morally reprehensible character.
Moreover, her future husband is immortal and isn't bad-looking either. He looks exactly like the King of the Sidhe or Fae in her old world with flowing white hair and bright blue eyes and porcelain skin. For certain, she will bear beautiful children with him.
"Then, we have a deal," Harriet replies, smiling.
AN: Were you expecting something different to happen? I bet you weren't expecting that. *insert evil laughter* Anyway, I've taken the book description of the Others instead of describing them as depicted from the show. I've read from somewhere that the Others look like the Sidhe or Fae of our world.