What do you think of this idea for a story?

the town of David is invaded by killer alien insects called Zephron, one day sees the boy sitting on a bench a girl that does not seem to fear the sting of insects (she is immune), suddenly from the girl's mouth goes a long tongue, similar as frog tongue,that grabs the zephron. David and his friend Charlie discover that the Huntress is an alien too. she was bringing the bugs to the her planet when it was hit by asteroid. The two boys decide to help her to be recognized as heroes by city. But the human food makes zephron stronger (the size remain the same) and the Huntress is in trouble (insects can even pull her tongue in each direction for free itself).and get killed,David and Charlie died because of zephron's sting. and the world end.