He'd gone a full decade back. The dead body on the floor in front of the check out desk of the library belonged to Kendra Young. The Slayer Called when Buffy drowned. The Slayer whose throat had been slashed by Drusilla. As Xander looked around he realized Giles was gone. So Drusilla and Angelus already had him. Which meant Willow was unconscious and Buffy was doing something she did very well. Walking into a trap because she always believed she knew what was going on and didn't actually have a clue. She ignore facts. Facts like Angelus set traps and she fell for them each time because she wanted to believe Angel was somehow still in there. He wasn't.
Xander felt the pain of a broken arm, but ignored it. He healed a hell of a lot faster then any of them had ever noticed. Not until he'd regrown the eye Caleb had gouged out. Only then had anyone noticed he just didn't get hurt much and recovered much faster then he should have. Buffy and Willow had wanted him to be normal. Buffy, so she could live vicariously through him and Willow because she wanted him to be the Xander in her imagination. Neither were ever going to be true. He had twenty four hours. He was going to make the best of them.
First, he called an ambulance. Second, he hid the weapons from the book cage like he'd done before. It wouldn't do for the police to find them. Third, he destroyed Willow's Magic supplies. If she couldn't do the damn spell, Angel would never be brought back. The soul would never be forced to suffer both in a Hell dimension or by having to feel guilt for crimes it didn't commit.
He rode in the ambulance with Willow. He needed to make sure Cordelia was alright. Then he'd get what he needed to deal with the next problem.
At the hospital he held Cordelia for a moment. Their break up had destroyed him and he'd never understood it. Sometimes he'd wondered if Willow got going on the mind raping sooner then had been discovered. Other times, once he'd heard about all the manipulation in Angel and Cordelia's lives, he'd wondered if Jasmine had been responsible. Because he'd never felt anything for Willow like he'd felt for Cordelia and later Faith. If it was Willow or Jasmine, he had some ideas on what he could do about it. First things first though.
He headed out to the Army Surplus store. If he was going to do this, he was going to do it right. He bought a vest, complete with neck guard and a helmet. Being seventeen physically no one would sell him a gun or ammo. Didn't mean he couldn't dust vampires. He'd learned a hell of a lot over the years. He picked the locked on Giles' condo. He had alcohol and Xander needed it. Prime stuff. Oh well, the world would hopefully be a better place for the sacrifice of all that fine and expensive liquor.
Now to get Giles out. He wasn't waiting around for Buffy who wouldn't arrive until morning. Giles was being tortured now. He took a lesson from Giles and improved on it. When Giles had attacked Angelus seeking revenge for Jenny's death, he'd thrown the alcohol on the table instead at the vampires because he's wanted to personally dust Angelus. The bottle wouldn't break if it hit Angelus but it would if it hit the ground at his feet.
Xander lit the rag and threw the bottle and it landed right at Angelus' feet. The alcohol splashed onto his legs and the fire spread up them and he dusted screaming. A second bottle took out Drusilla. With them dusted Xander doused the fire with an extinguisher and untied the unconscious from pain Giles and half carried him out of the mansion. Spike hadn't been there, but if Xander remembered correctly, he was currently offering Buffy a deal to get him and Drusilla out of town safely. Spike would probably never know who was responsible for Drusilla being dusted.
Xander dropped Giles at the ER. He was conscious of every second he had to try to leave a message for the Scoobies about the future. Just because he couldn't tell anyone, didn't mean there weren't other ways of communicating. Once the stores were open he went in and bought supplies. He was going to try a variety of ways of leaving a message about the future and hoped one of them worked. He'd never know himself.
He was getting frustrated. Writing the information down didn't work. It didn't matter if he used pens or pencils, nothing transferred to the paper. Intellectually he understood. Technically he was changing the present by dusting Angelus and Drusilla. That he did it using knowledge that came from the future was beside the point. Leaving a record of future knowledge, a future that might never happen now because of his actions was something else.
Okay, maybe there was another way he could do this. If he couldn't leave future knowledge, maybe he could hide future knowledge until the time synced up. If he used Magic, something he'd learned how to do in the future, to hide a record, a record that would only become visible at a certain time, that might work. It was worth a shot anyway. But this was why he didn't like Magic. It played by its own rules. Rules that both did and didn't make sense.
Using Magic he put a bubble of time around the paper and when it reached a certain date he wrote his message. It worked. He did it again and again until he'd highlighted every major Big Bad that might still be an issue. The Mayor, Adam, Glory, Willow and the First.
Then he cast protective Wards over his younger body and mind. If Willow or Jasmine wanted to manipulate him he was going to make it as hard as he could. Then he Warded a necklace and mailed it to Cordelia. He had to do it anonymously but he knew what she liked. Hopefully he's done enough to change the future.
He returned to the hospital and found Willow and Giles still unconscious. Cordelia and Oz had gone home. It was a good thing he was there because when future Xander ceased to be, present Xander passed out.