In Lyoko, Christmas was called by its original French name, Noel. It was a mixture of different customs, primarily ones that were reminiscent of Asian ones on Earth. Poor XANA though, still under Umbra's power, wasn't able to enjoy the festivities though, in his mind, he could see himself under the brilliant golden candles enjoying fruit pies and the bounty that the fall had provided for the land. Though he couldn't celebrate with his fellow Lyokians, they were also nestling down to slumber for the night before Christmas day arrived. It was a joyous time to be had by all, even in the virtual world, and even they were enjoying their own winter wonderland, coincidentally enough.
While XANA was dreaming, he was blissfully lost in an oneiric version of Earth, and in his dream Sissi was courting him. XANA knew that besides the Princess Aelita and the other Lyoko Warriors, Sissi was one of those who could break XANA away from the horrid curse that was controlling his heart, mind, soul, and body. When they were able to free him from his curse, he would finally be able to enjoy life with his people. But for now, his heart was tainted with the worst evil that the Lyokians have ever seen, and he couldn't stop it himself.
"You can't deny me any longer, XANA.", Umbra stated, as he noticed XANA's attempt at breaking the link between him and Umbra.
"Why now, at such a harmonious time ?", XANA thought, banging angrily on the sphere that surrounded him. Even if he wanted to combat Umbra's plot, he couldn't. So, he had to do the unthinkable and contact the Warriors with telepathy.
Of all the seasons and all the holidays that existed in the universe, Umbra despised Noel the most of all. He particularly loathed joviality, frivolity, peace, tranquility and merry music. Umbra had spread a dire darkness and sadness amongst the Lyokians, destroying presents and decorations in his wake. If there was one thing he hated it was joviality. In a matter of seconds, he heard the sound that gave him ultimate pleasure; sorrow, pain, and screams of pain and sadness, tears flowing down the children's cheeks.
The Warriors sprung into action immediately before Umbra had the chance to spread his vines of sorrow to one of the last children that looked onward with horror to the oncoming darkness. One by one, Warriors with sharp weapons destroyed the tendrils while others attacked him head on. Umbra began to feel fear himself, particularly when he felt his life-force fading. He couldn't risk another attack without being subject to the power of having his own fear turned against him. With some upset and anger, he had to flee the battle before the delivering blow was dealt. In a blink, he put himself into stasis and strangely, XANA fell out of his prison. After seeing what had occurred, XANA tried to return the landscape to normal but could do nothing. In a single, solemn movement, the Warriors gathered together, held hands and sang Silent Night. XANA, surprised, sang along, and before his eyes the landscape resembled its former pristine beauty. His eyes watered a bit, and he didn't know what to say. He was just pleased he was free from Umbra's clutches for the time being and at least he could enjoy the festivities of Noel. Knowing XANA was grateful; the Warriors took their leave and returned back to the cabin long before anyone had known they had left.