Spiritomb

One night...
Dawn and Ash were doing some training with Aipom and Buizel. Because of their recent trade, they wanted to get used to using them. Ash was checking Buizel out with the Pokedex; aside from knowing Water Gun, Growl, Aqua Jet, Sonic Boom, Swift and the egg moves Slash and Fury Swipes, Buizel also knew Hidden Power and to everyone's surprise the type Buizel's Hidden Power was is electric. 
"Okay Dawn, let's make this a good practice battle." Ash said.
"Let's." Dawn agreed.
"Aipom, Swift." Buizel countered it with his own Swift.
"Buizel, Aqua Jet." Ash ordered.
Aipom used Mimic and use Aqua Jet to counter Buizel's.
"I'm so glad that you and your Pokemon had Aipom learn so many wonderful moves Ash." Dawn said.
"Yeah, but it won't beat me yet." Ash said.
"Buizel, Sonic Boom." Ash ordered.
Aipom deflected it with Focus Punch.
Unfortunately Buizel's Sonic Boom attack was flung straight to a hallowed stone tower and crumbled it to bricks.
"Oh no!" Ash gasped. 
He and the others ran to the broken tower. Just then the crumpled bricks began to glow.
"What's going on?" Tomo asked.
Before Tomo's question could be answered, it suddenly got very cloudy and there was a chill in the air.
"I'm feeling a strange aura here, and it feels evil." Ash said. 
Suddenly a thunderbolt from the sky struck the pile of bricks and then a strange stone in the rubble began to glow purple and an eerie voice saying 'Spiritomb' was heard. 
"What's that?" Dawn asked.
A purple and green phantom-like Pokemon appeared out of the stone, answering Dawn's question.
Dawn looked at the thing on the Pokedex.
"Spiritomb, the Forbidden Pokemon. A Pokemon that was formed by 108 spirits. It is bound to a fissure by an Odd Keystone." 
The Spiritomb started to attack the gang with Shadow Ball and Hyper Beam. Ash was angry.
"Buizel, Water Gun." He ordered, but Water Gun didn't do much. Then Spiritomb used Dark Pulse and knocked Buizel out. After that Spiritomb flew away.
"What in the world was that about?" Dawn asked.
"I don't know, but that Spiritomb is one bad Pokemon." Ash said. 
The others agreed.
The next group of people to meet Spiritomb was Team Rocket. They were spending the night around a campfire and having some biscuits and rice balls.
"It sure is cloudy tonight." Meowth said. "I hope that it doesn't rain." 
Then Spiritomb showed up and attacked Team Rocket with Hyper Beam and Dark Pulse and then flew away again.
"What was that?" A irate Jessie asked.
James had a look at his Pokemon book and explained it was Spiritomb. 
"It says here that Spiritomb is a very bad Pokemon and it loves causing destruction and mayhem wherever it goes. And it also says it was sealed away 500 years ago for it's wickedness." 
"Do you think the boss would like this kind of Pokemon?" Meowth asked.
"Absolutely." Jessie said. "That kind of power is just the boost Team Rocket needs." 
So Team Rocket's next plan was to catch Spiritomb.
The next day...
The gang continued walking.
"I can't get that Spiritomb out of my head." Ash said.
"Yeah, especially since it was so aggressive." Dawn said.
Suddenly they came to a village and it looked like it had been attacked because some houses had been destroyed and a lot of Pokemon that lived in the village with the villagers were knocked out. 
"What happened?" Ash asked a boy with a Raticate.
The boy explained that a creepy Pokemon came and attacked the village out of nowhere. The gang believed that Spiritomb might have done this. Suddenly an old woman started shouting that it was a Spiritomb that had caused the destruction.
"Excuse me madam, but do you know about Spiritomb?" Ash asked.
"That I do, young man." The old woman answered.
The old woman explained that 500 years ago Spiritomb caused destruction in the area by destroying homes, fields and trees and made people's lives miserable. But one day an aura guardian with a Pikachu for a partner came and fought Spiritomb. Spiritomb ended up being knocked out by Pikachu and after it was defeated the aura guardian sealed Spiritomb's key stone in a hallowed tower made out of stone so it would never cause trouble again. Hearing the story made the gang remember the hallowed stone tower they destroyed last night and figured that was it's prison.
The gang led the woman to the broken stone tower and the woman was shocked when she saw it.
"I take it you kids had something to do with this?" The woman angrily asked.
The gang explained that their Pokemon were training and their attacks hit the tower by mistake. The woman sighed.
"The Spiritomb was sealed by a aura guardian with a Pikachu." She said. "And now it has been unsealed by some reckless kids who have a Pikachu with them. The ways of fate can be so strange sometimes."
"Since it's our fault Spiritomb was released we must defeat it and seal it away again." Ash said.
"But how Ash?" Dawn asked. "You've seen how strong that Spiritomb is."
Ash looked Spiritomb up on the Pokedex again and looked for any weaknesses.
"It says that Spiritomb is a ghost/dark type Pokemon and doesn't really have a weakness." He said. "But it does say that if we use a Pokemon with Foresight, Spiritomb will be weak to fighting type moves."
"That's good to hear." The old woman said. "Do any of your Pokemon know Foresight?"
"Yes, my Riolu does and it's a fighting type Pokemon." Ash said.
He quickly used his Pokedex to get his Riolu from Prof. Oak's lab.
Suddenly they heard a scream come from the village; Spiritomb was back. Ash was just about to release his Riolu, but then a Solar Beam hit Spiritomb; it didn't do much damage though. The attack came from James' Roserade; Team Rocket released all their Pokemon to battle Spiritomb so they could catch it. Unfortunately, even all of their Pokemon's combined strength wasn't enough against Spiritomb. Spiritomb easily defeated their Pokemon with Dark Pulse, Shadow Ball, Hyper Beam and Giga Impact. After returning their Pokemon Team Rocket tried to run away, but Spiritomb sent them flying with Hyper Beam.
Now that Team Rocket was gone Ash stepped forward.
"Let's do it." He announced, releasing Riolu.
"Riolu, Foresight." Ash said.
Riolu released two blue beams from his eyes and covered Spiritomb. He could now use normal and fighting type moves on Spiritomb.
"Now Aura Sphere Riolu." Ash said.
Riolu threw a Aura Sphere at Spiritomb that hit it.
"My turn now." Ash said.
He also released a Aura Sphere that hit Spiritomb. The old woman was surprised after he did that. 
"Is your friend an aura guardian?" She asked Brock.
"No, Ash is not a aura guardian, but he is a aura user." Brock explained.
Ash and Riolu led Spiritomb away from the village and into the area where the crumbled Hallowed Tower was.
"Okay Riolu, time to use Aura Sphere again." He said.
He and Riolu attacked Spiritomb with Aura Sphere together. Spiritomb was becoming angrier by the second. Seeing Ash use aura made him realize he was a aura user. Spiritomb wanted to get revenge on the aura guardian that sealed him away 500 years ago; that wasn't possible though because he was dead. Seeing Ash use aura caused Spiritomb to think he was a descendant of that aura guardian. That wasn't true, but Spiritomb believed it. Spiritomb then prepared to use Giga Impact.
"Quick, our aura shields Riolu!" Ash shouted.
He and Riolu created a aura shield together to protect themselves from the attack. They were getting tired, but Spiritomb wasn't backing down yet and it got ready to attack again.
"We can do this Riolu." Ash said. 
'Yes we can, papa.' Riolu mentally said.
Suddenly Riolu glowed and evolved into a Lucario.
Dawn looked it up on her Pokedex.
"Lucario, the Aura Pokemon and the evolved form of Riolu. It has the ability to sense the auras of all things. It understands human speech."
"Okay Lucario, use Foresight again and we'll both use aura again and Pikachu, you use Thunderbolt." Ash said.
'Yes, father.' Lucario mentally said.
Even after evolving, Lucario still considered Ash to be his parent. Lucario used Foresight again and then he and Ash used Aura Sphere while Pikachu used Thunderbolt. Spiritomb was badly injured by the three attacks and then it's body went into the keystone; it had been defeated.
Ash hugged Pikachu and Lucario for a job well done. They were exhausted after the battle, but happy they finally defeated Spiritomb. 
"Quickly now." The old woman said. "We must seal the keystone in the Hallowed Tower."
Brock picked the keystone up and carried it to the stone tower; it was heavy, but Brock moved as quickly as he could.
Together the gang rebuilt the stone tower back to how it was before with the keystone inside. Then the tower glowed again; that meant that Spiritomb was sealed away, no longer able to cause anymore trouble.
"I think we should put up notices here to warn people about the Spiritomb sealed in this tower." Ash said.
"I think that's a great idea." Brock agreed. "Especially considering we don't want this to happen again." 
The old woman promised she would put up warnings here.
"Now a new legend is born." The woman said. "The revived Spiritomb was sealed away again thanks to an aura user and his loyal Lucario and Pikachu."
The gang chuckled after hearing that, even Pikachu, Growlithe and Lucario couldn't stop giggling. By now, it was night time and the old woman invited the gang to stay at her place and have dinner here tonight. The gang immediately accepted due to the day's excitement.
So with Spiritomb sealed away, the gang was able to get a good night's sleep.