If Firestar was rejected: An AU

Rusty climbed over the fence, and breathed in the smell of the forest. Purring, he ran deeper in. He stopped by a clump of grass, and stretched, his collar tinkling. Suddenly, something leaped out of the grass, aiming for him! Landing on top of Rusty, it was a grey tom, with no collar. A blue-grey she-cat padded out. "That's enough, Greypaw." she said. The grey tom slid off Rusty. "Now, what are you doing here?" said the blue-grey she-cat. "I just want a look around. I'm not doing you any harm." replied Rusty, scared. Hissing, the blue-grey she-cat took a step towards Rusty. "We find it hard enough to feed ourselves. The last thing we need are kittypets stealing prey! Now, scram!" 
Rusty bolted, leaping over the fence. He felt his heart pounding. He couldn't go back to his housefolk though. That had been why he left. No. He started walking towards an alley. Rusty was a stray. "You, with the ginger coat." he heard. Looking around, he saw an old grey she-cat. "Yeah, you. You hungry?" she said. Rusty nodded. "It- it's okay?" 
"I can't resist kittens down on their luck. Here." replied the old she-cat, pushing over a piece of the food. Rusty started eating, too hungry to be careful. "Thanks! This is good. What is it?" he asked. 
"Chicken. I always get a bit, so don't feel like you're stealing anything." replied the she-cat. She lifted her head. "Who's there?" she asked. A tiny black kitten with one white paw poked his head around the corner. "Just me." said the kitten, coming forwards. "Can I have some?" he asked. The she-cat tossed him a bit.
"Here." she said.
"What's your name?" asked Rusty, cautiously taking a step forward.
"I'm Tiny. You?" said the black and white kit.
"I'm Rusty." said Rusty. "Why don't we help each other?"
"Sure!" said Tiny, coming up to Rusty.
The next day, they couldn't find the old she-cat. They were exploring twolegplace looking for food, when they saw a dog. "Eek!" said Tiny. "It's a dog!" the dog stood, and padded out of the alley. On the ground, there were two teeth. Tiny took one. "Maybe we can get our collars off." he said. Both of them tried, but the teeth just got stuck in the collars. "Stupid collars!" said Rusty. 
Later, the two toms saw a group of strays with food. "Excuse us," said Tiny. "But can we have some?"
The strays looked up. "Where'd you get those dog teeth?" asked one. Tiny blinked.
"We took it from a dog! It was trying to get to some food we'd stashed away! So we fought it, and once it was dead took these teeth from its mouth as a trophy!" he said. The strays looked the two young toms up and down. "Is that true?" they said. Rusty gulped.
"Yes!" he said. The strays looked unconvinced, but they stepped back. 
"Help yourselves." they said. Later, the two toms curled up in a tire. They should have known it couldn't last. They woke to a voice calling them. Looking over, Rusty saw two cats, one with sandy fur, one with black and white fur. "Is it true that you fight dogs?" asked the black and white one. Tiny looked at Rusty. "Yes. Why?" he said. "I'm Bone, this is Brick. Follow us." Rusty felt his heart plummet. What had he gotten himself into?
.Rusty followed Tiny, Bone, and Brick.
"Hey, you there." Brick snapped at him. "Back off. We don't want you."