Theory:

The poem is about a dog which is left alone outside on a fireworks night. He is scared because of the banging sounds. He thinks the fireworks are gunshots. It is dark and cold outside, and he pleads to his master and mistress to let him inside before the fireworks begin again. His tail had gone down, and his ears had become flat in fear. He asked them if they don't love him anymore and thought he would die in fright. Finally, the master and mistress open the door after asking their children. The dog rushes inside happily, and the lights provide him with warmth and safety. He licks his mistress's hands and crouches behind the sofa. He says he will soon return to his kennel once the bangs are done and continue to guard the family.
 
firework dog.jpg
Mistress, Master, hear me yelp, I'm out-of-doors, I want your help!