Jiang Cheng was sitting in a corner with a vapid expression while Lan Xichen was  sitting next to Nie Huaisang.
All juniors, Wen Ning and Lan Wangji entered the room after inspecting the Unclean Realm.

"Xiong-Zhang." lan wangji informed.
"So the array was for soul summoning?" Lan Xichen asked.
"Mn."

"I see...Wangji, take a seat."

Lan wangji was startled from the tone of it, it was something serious. He did what he was told.

"Wei gongzi-"

"Stop."

Lan wangji didn't want to hear. After examining the arrays, he knew what had been casted there. He didn't want his brother to confirm his doubts.

"Wangji" lan Xichen continued again, "We can bring Wei gongzi back." 

He really did leave him.

"Xiong-Zhang!" His tone was so painful that even Wen Ning felt it.

"I want everyone's help here. It's bit dangerous so if you do not want to partake, you may step back." Lan Xichen addressed to everyone. They all nodded in agreement without a second thought. Lan wangji felt so grateful that he bowed to them all.

"Can someone explain what really happened?" Jin Ling broke the silence and went to purple figure, "Jiujiu?"

"Wei Wuxian... He.. he left the mortal realm..."

Their expression darkened, Lan Wangji's knees gave out as he fell on the ground while Lan Shizui quickly went to him. Lan Xichen added to lift their worried expressions,

"He's not dead."

Everyone looked with confusion and demanded questions.

"How did he even leave the mortal realm?" Lan Jingyi being the brave lan asked.

"....things happened....what's important is that he's not dead and he can be brought back."
Lan Xichen knew that juniors won't be satisfied with just this but he respected Nie Huaisang and kept things secret, he didn't even let Lan Wangji know.

"Xiong-Zhang." Lan wangji looked at his brother with a look that translated his pain of those 13 years.He wanted Wei Ying back right that instant.

"I need your spiritual energy to draw an array. It's different than the arrays we draw and it's also just a speculation so it may not necessarily work-"

"... we will open the Heavens Gate."

The crew went silent. Heavens Gate? They only heard about it in the books was it even possible?

In reality Wen Mao was the first one who tried to open the Heaven's gate, his cultivation was strong and he had rich imagination, just like that Baoshan Sanran attempted it. It was not clear whether they succeeded or not but the the witnesses were so scared that they immediately banned it and ever since then it is studied under the forbidden category.

"How do you know this is the right method?" Zizhen asked being the rational guy that he was.

"Wei Wuxian said it himself." Jiang Cheng replied instead.
"He opened the Heavens Gate just moments ago to leave the mortal realm, you felt it didn't you? "

Crowd nodded in agreement, it was that surge of powerful energy that made Wen Ning rush to Wei Wuxian. He knew how dangerous the Heavens Gate really was. And it was impossible to open the Heavens Gate till now? Only Yiling Patriarch would attempt something like that.
Attempt the impossible!

"Why would Wei Qianbei open the Heavens Gate?" Jingyi asked again. This time Nie Huaisang replied ,
"I told him that I wanted to talk to someone but things didn't go how I expected."
Lan Wangji surged out at this, Lan Xichen noticed and calmed his brother ,
"Wei gongzi Is alright. Before entering the Heavens Gate he instructed Sect leader Nie about it So, we could bring him back."
Lan Wangji was urged to take a deep breath by his son.
"But we need to prepare before performing the ritual, you may rest till then, I will call you once I'm done with first array."
The juniors have left the scene with Wen Ning, they knew there's nothing they could do there right then. 

"Jiujiu?" Jin Ling called Jiang Cheng, upon no response he left with others.

                                                                                 . . . 

Lan Wangji was restless and only Lan Xichen could see that.But he couldn't really do anything to make him feel better. That brought his spirits down.

"That damn Wei Wuxian! He thinks dying is a game! Causing trouble even when he left!" Jiang Cheng scowled.

"Wei Ying is not dead!"

Lan Wangji stated making things clear, clear for himself. Now that he said it out loud he actually felt better about it. He reassured himself that his husband was alive and would come back.

Lan Xichen was done with the first array, it was a big one and clearly it took him a lot of effort and blood.Of course, Lan Wangji, Jiang cheng and even Nie Huaisang offered their blood but the Heavens Gate required a bond. 

Heavens Gate was the boundary between life and death, it couldn't be just breached with anyone. To open the Heavens Gate, a large sum of spiritual energy was required. Theoretically, it could only be opened by someone with crazy huge spiritual energy but none of them really fit the criteria.Not even Lan Xichen. They were strong yes, but not enough to even summon the Heavens Gate. Next option was to collect the spiritual energy from large group of people, same way the founder of cultivation and the great immortal had practiced. Heavens Gate required triple magic array. 

One of Spiritual energy.

One of Blood. 

and One of Soul.

it was dangerous!

He's still alright after all that? Jiang Cheng thought.

 it's true Lan Xichen was the one with the strongest cultivation among them. Jiang Cheng and Lan wangji would rival each other , while Nie Huaisang would barely match the juniors and Wen Ning? He was dead so he didn't count. 

                                                                                 . . .

"Before performing the ritual, I want you all to meditate and clear your minds." Lan Xichen instructed everyone.

"I can't get rid of all the thoughts though , they keep coming on their own -bad ones" lan Jingyi made it clear and caused Jing Ling and Zizhen to slap their faces.

"How bad?" Lan Xichen inquired.

"... sneaking chicken wings in my room after training?"

Lan Jingyi looked down readying himself for a scolding but he only hears a mild laugh. His eyes widened on seeing the source of it and he was sure he would die.

Sandu Shengshou laughed!?
Jiang Cheng was reminded of Wei Wuxian, only he would do or say something utterly stupid in a deadly situation. It really shocked everyone except Nie Huaisang. He's been a part of it too once, with the two of them.
The thought filled him with the guilt. What have I done?

"You'll be alright." Lan Xichen took out Leibing and played a tune, it really did calm them all.

They all stood on each tangent of the first array. With blood they bonded with the first array and with their Golden Core they begun to create the second. They channeled their Core through one of Qiqao point.
The moment their first array combined with the second, they felt drained. Their spiritual energy was seeping out. They felt heavy. 

and the third array....

The windows flew open with the streak of  thunder and the sky cut through them creating a flash of lightning amidst, the resentful energy circled around them. It was too heavy, it was too ....painful!

How did Wei Wuxian manage to open the Heavens Gate all by himself? How did he cope with such strong resentful energy?

The screams filled their ears and sent a wave down their body. Juniors started trembling with fear but none of them dared to let go of the array. The moment their spiritual energy escaped out of them,one by one they fainted.

Only the twin Jades and Sandu Shengshou remained - barely standing. The Same thought ran through their mind,

'How do you do this, Wei Wuxian?'

The screams echoed in their brains, all the cries and sobbing, all the destroying thoughts, all the self hatred, all the resentment, it was too much.
They wanted to scream too but their screams would be overpowered by the howls of pain around them.

'You were listening to their cries alone! You took it upon yourself to listen to them... It's lonely...'

Jiang Cheng spat out blood, the resentful energy was having its toll mostly on Sandu. Reviving all the forgotten hateful things in him. Lan Xichen only able to muster enough energy to hum a tune and Jiang Cheng fainted, followed by Lan Xichen, he truly spent himself.

Lan Wangji refusing to close his eyes. He bit his lips till it bled. Just before he lost consciousness, he saw
A black figure stepping out of the light.

"...Wei...Ying...?"

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Sorry for Errors and thank you for reading.