Imagine this:
After yet another night attack, Astrid heads into the woods for her usual morning training session. While walking, she flings her axe at a tree in the distance and then walks over there to pick it up and fling it again. In the meantime she whistles a relaxed tune. While molesting the forest, she thinks back at the moment only an hour ago. That lunatic Hiccup had embarrassed himself in front of the village again, causing another accident and after that still claiming to have shot down a Night Fury, whilst all the other villagers strangely enough weren't paying attention. Astrid laughs at the stupidity; how could he possibly expect any sane person to believe him?

Then, she hears a growl. Quickly running towards her latest wooden victim, she tugs the axe free from the bark and takes a defensive position. "Still hungry, dragons?" She mumbles, even though her heart beats wildly. "Well, I'm no good for a desert. I've got an after-taste that you might find un-axe-eptable." There is another growl, but this one sounds more woeful. Having pinpointed the location where the moans are coming from, Astrid heads forward. The first disturbing sign she spots is a broken down tree, with a deep trail in the soil heading over a hill-top. The groaning monster has to be on the other side of it, the Viking girl thinks. Slowly, carefully, she peers over the edge.

There it lies; a black terrifying creature, probably three or four sheep in length, his legs and wings entangled in ropes. It is snaking around, trying to free itself from the tight grip, but that's futile. Knowing that the dragon could not break loose or attack, Astrid approaches it to get a better look. "Wauw, amazing," she gasps, walking towards the dragon. It looks up at her and growls softly. But Astrid isn't scared, although she stays well away from it's head. Who would leave a dragon alive after capturing it? She wonders. What kind of dragon is this anyway? A Timberjack is bigger… A Gronckle is sturdier and has smaller wings… And monstrous nightmares only have two legs, walking with their wing claws.

Then, with a gasp, she realizes what it probably is. "A Night Fury?" She asks aloud, as if the dragon could answer. The beast sees the axe the girl is holding, and knows that she's going to kill him. Admitting his defeat, he lays his head on the ground, sighing deeply. Astrid scans the dragon again. "It has to be a Night Fury," she says to herself. "Not a single dragon in the Manual looks like this." At the same moment, she realises the dragon wasn't left behind here. He had crash-landed here. It has been shot out of the sky. And finally realising that, Astrid remembers the unbelievable story of the village's black sheep. "Hiccup did this?" She wonders. "I can't believe it. He actually shot one down? And a Night Fury for that matter. He's a geni-" She clasps a hand over her mouth just before the word could entirely escape. There was no way she would ever admit something as embarrassing as Hiccup being a better dragon killer than she was.

But, then what?, she thinks silently. What are my options? She could tell the villagers, admitting Hiccup's great heroic action. "No way." She shakes her head, dumping the hideous idea. She could leave the dragon be, and continue her training. But if Hiccup was crafty enough to make a friggin' Night Fury fall from the sky, he could probably locate the beast's landing site as well. And when that happens, he would still be the greatest Viking of all. So that's no option either, she thinks, her back crawling at the idea of Hiccup being her superior. Then there is another option; move it. Astrid looks at the dragon again. It quickly shuts his eye, as he had been watching her, waiting for her to strike the finishing blow.

But, there's no way I can move him on my own, she thinks sighing. Then I would have to release it, so it can- "Argh, what am I thinking!" she yells, startling the dragon, which growled annoyed. "You're a dragon, the toughest one to catch for that matter! I could just kill you, claim you as my kill, and become an even bigger protégé than I already am! What do you think of that?" The dragon gazes straight at the girl, moaning frightened. Only now Astrid notices she had been talking to the dark creature, as if it is a rational being. All of a sudden, killing the poor thing seems as a terrible thing to do. But still, if she would release him, he would simply attack the village again and again. "I can't release you, right?" Astrid mumbles. "There is no way that you would promise me to stop attacking us if I released you." The Night Fury raises his head, staring at the girl. He looks almost hopeful.

Then Astrid hears a terribly familiar voice. "…or a mug. No, not me, I manage to lose an entire dragon! Au!" The dragon looks up at the hill, grumbling fearfully. Astrid feels pitiful, and without realising what she is doing, she leans towards the dragon's head, touching it's flank gently. "Listen, dragon," she whispers to the beast, "that guy over there is absolutely going to kill you. He's the one that shot you down. Now, I'm going to cut you lose, and you fly off, alright? Don't make a sound." Astrid pulls the ropes towards her axe's blade, cutting them one by one. She quickly grabs the pieces together and hurls them into a bush. The Night Fury glares at her for one more second, before it spreads his wings and flies away. Astrid sighs relieved, but then sees how the dragon struggles to gain height, and even crashes into a heap of boulders. She hears Hiccup gasping behind her. Did he see it?

"G- Get back here, you coward!" she yells after the beast, which is still struggling to fly away. She gasps a few times, making it seem as if she just had a fierce battle. Turning around, she now faces the scrawny boy.
"Wha- What was that? Are you OK? What just happened?" he asks completely flabbergasted.
"Ow, nothing, just-" Astrid tries to calm down and make up a lie. "Just a Nadder that was looking for breakfast. What are you doing out here? Aren't you supposed to be grounded?" Hiccup blinks a few times. It takes him a while longer to change the subject from Astrids fight to this confrontation.
"Er, I uhm," he stammers, "I was looking for, eh-" Astrid grabs him at his jacket, sighing irritated by the fact that this was the only way to make him forget about this.
"If I get attacked like that, it's even worse for you to be out here," she says. "Your father won't like to hear that you left your house."

"What? No, no, no, no, please don't tell him," Hiccup begs, grasping Astrid's hand. "He's mad at me already. This time it's going to be more than just a scold. Just let me go, I'm only looking for- Aaaaaaaw, why would you do that?!" He moaned as Astrid twists his arm.
"That's for touching me," she says devilishly, hitting him again with the heft of her axe. "Now get a move on. I can't train with you running free." Dragging the half-unconscious wimp along, she returns to the village. The Viking girl looks over her shoulder a bit uncertain. Never is she going to understand why she did what she just did; by not only not killing, but also granting a dragon freedom, she has broken two of the most important Viking rules. I hope it was a good idea to release you, dragon, she speaks in mind.

A/N: And there is more to come, because the movie doesn't end at this point! :D I'm planning on writing a possible outcome of all the events, following Astrid while she tries to keep Toothless a secret and how she handles things. Reviews are greatly appreciated. =3 Thanks for reading!
EDIT: Thanks for the reviews, TheCrazyArtist and Sithking Zero. I've changed it in this chapter and will follow this style in the upcoming chapters as well.
Please tell me if anything else needs improving! =D